DanH

There's a rule for factoring this type of polynomial: x^3 - a^3 = (x-a)(x^2 + ax + a^2) Can you take it from here??

17 years ago

You need to translate the information they give you to algebraic equations. Remember, an isosceles triangle has 2 sides equal to eachother and one not. So, if you call x the length of the sides that are equal, and y the length of the base, then you can ma...

17 years ago

This looks like a "prime" quadratic. With trial and error trying: (-4t )(t ) or (-2t )(t ) you cannot get it to work. So there are no "interger" solutions. You can use the famous "quadratic equation" to get an approximation. ARe you familiar with this?

17 years ago

ok. I assume you know the quadratic formula. It is hard to write it here. In your example, a = -4, b = -9 and c = -3. So, when you plug these in, you end up with (9+sqrt43)/8 and (9-sqrt43)/8 this is approx: 15.56/8 and 2.44/8. These are your 2 solutions.

17 years ago

see below

17 years ago

woops...slight mistake. It's actually: (9+sqrt33)/8 and (9-sqrt33)/8 or 14.74/8 and 3.26/8.

17 years ago

Do you know what the plural of leaf or knife is?

17 years ago

you are right!

17 years ago

now cancel your x+1 and you got it... actually I got over 1/(x-4)(3x-2)...slightly different.

17 years ago

It is right!!

17 years ago

this is right.

17 years ago

you're right!!

17 years ago

I am sorry, but the second part of the problem "express your answer to the question as power of 2" is confusing to me. Certainly, if you flip the coin TWICE, then it's a power of 2, as you said, but if you flip it N times, I don't know you can express thi...

17 years ago

correct!

17 years ago

correct

17 years ago

the answer is 8x^2 - 13x - 14...but there is no denominator. If I understood it right, initially there is 1/2 in the denominator. To get rid of it, you mulitiply it by 2/1, and it cancels out. then you also multiply the numerator by 2/1, to get the answer...

17 years ago

correct

17 years ago

no problem. you're doing very well!!

17 years ago

Oh...ok, of course... 2^-n is the same as (1/2)^n.

17 years ago

you got it!!

17 years ago

woops. this one, if I'm seeing it right... you would have (7-2x^4)(7-2x^4), and then you have to use the "FOIL" method...right?

17 years ago

(7-2x^4)(7-2x^4) first, multiply the first two: 7x7=49 then, multiply the outside two:7 x -2x^4, which is -14x^4. then, multiply the inside two, which is also -14x^4 then, multiply the last two: (-2x^4) x (-2x^4) which is 4x^8. so, we have: 49 -14x^4 -14x...

17 years ago

yup

17 years ago

you need, of course, to factor this. Start by doing this: (x^2 - )(x^2 - ) =0 Can you fill in the blanks?

17 years ago

6^3 is perfectly correct.

17 years ago

yes.... you have x^2 - 6 = 0, so, x = + and - sqrt6 AND x^2 - 3 = 0, so, x also = + and - sqrt3

17 years ago

yes!! so you have it factored. Then to get the "roots," set each one equal to 0.

17 years ago

Ba is ++, and NO3 is -. So, it's Ba(NO3)2

17 years ago

That is correct, although you may want to keep it to 2 significant figures, since the first volume is 2 sig figs: Vf = 0.32 cubic meters.

17 years ago

yup, simple as that!!

17 years ago

I'd pick the last second one you wrote.

17 years ago

I'm sorry. I really don't know what they mean by "variable substitution!"

17 years ago

The answer you have is correct, but it is the CHANGE in length, not the new length. So, the new length is the old length (1.2m) + the answer you came up with.

17 years ago

correct

17 years ago

you need to factor out an x out of each, so the answer actuall is: x(x-6)

17 years ago

The violet color will wash away with water. The reason for adding the iodine is that it chemically binds to the crystal violet, and makes a water-insoluble complex.

17 years ago

I think you are close. You will find that the distinction between organic and inorganic is often somewhat nebulous. Yes, in general, organic compounds contain carbon and inorganic do not...but not always!! for example, carbon dioxide, sodium cyanide, and...

17 years ago

yes.

17 years ago

Choice A is incorrect.

17 years ago

Your answer sounds excellent to me.

17 years ago

2) A is correct 4): I think the point of this question is that the teacher wants a RANDOM sample of students. The only choice that would really give her a random sample would be C. All others are biased.

17 years ago

yes, I agree: both ethanol and isopropanol have LOWER boiling points than water.

17 years ago

KE at base of hill gets converted into potential energy at the top, plus remaining kinetic energy of bicycle moving. Thus, KE(base) = PE(top) + KE(top). (mv^2)/2 base = mgh + (mv^2)/2 top. Note the masses cancel out. v^2/2(base) = gh + v^2/2(top) 400/2 =...

17 years ago

Since you have to ADD energy to the reactants in an endothermic reaction, the energy is on the left side: something + energy = something

17 years ago

First, calculate the velocity when he hits the water using: V(f)^2 = V(o)^2 + 2as Then, calculate the deceleration as he goes through the water using: V(f) = V(o) + at. Then you can get the force once you know a with F = ma.

17 years ago

yes, in my first equation, the "s" is distance, or in this case, height.

17 years ago

The x intercepts are where the equation Y is equal to 0. So, just set up equation: 0 = x^2 + 2x - 8. can you take it from here??

17 years ago

OK, you can do it that way. First, he has potential energy = mgh. This gets converted into kinetic energy. The kinetic energy when he hits the water is (mv^2)/2, so you can calculate his velocity when he hits the water. Then calculate his deceleration, an...

17 years ago

you're welcome!

17 years ago

The work done by the spring is the elastic potential energy, which is (kx^2)/2. The energy dissipated by the friction is the work done by the friction force (the friction force x the distance). These two things added together (the work of the spring and t...

17 years ago

You are correct!

17 years ago

The answer should be D...the author sites an opinion of an "expert."

17 years ago

you are correct

17 years ago

False. The energy of a wave is proportional to the square of the amplitude. So, doubling the amplitude increases the energy four-fold

17 years ago

multiply the top equation by 2...it becomes: 6a - 2b = 18. Then you can add the 2 equations together. The b's cancel out. you get 8a = 32. a = 4.

17 years ago

If the traits are on the y-chromosome, and are DOMINANT...that means that ALL the offspring BOYS will have the trait, but NONE of the offspring GIRLS will have the trait. Do you see why?

16 years ago

Yes, absolutely right!!!

16 years ago

Here's how you get 31: You are correct that a = -12. Do, now the function becomes: f(x) = x^2 - 12x + b. Now, we know that x is 6 and y is -5. So plug these in: -5 = 6^2 - 12(6) + b solve for b and get 31. Do you understand?

16 years ago

yes. Now, you need the second derivative, which in this cae is 6x. So, at the first "critical point,-1.4, the second derivative is negative, so at that point, so it is a maximum. At the second point 1.4, the second derivative is positive, so the graph is...

16 years ago

The time it takes to get across is 240m divided by 3.8 m/s, which is 63.2 seconds. In that time the current has moved boat downstream by: 1.6 m times 63.2 seconds, or 101.1 meters. Then to get the resultant velocity, you need to add the velocity vectors....

16 years ago

The slope-intercept form is y = mx + b, where "m" is the slope, and "b" is the y-intercept. So, here the slope 7/10, and the y-intercept is -10/7

16 years ago

No, that is not the answer I get when I plug in to the quadratic formula. I get (1 + sqrt7i)/2 and (1 - sqrt7i)/2 Do you understand how I got this?

16 years ago

Start by factoring the equation. Do you know how to do that?

16 years ago

You're welcome

16 years ago

sqrt(b^2 - 4ac). b is -1 and a is 1 and c is 2. So, sqrt(b^2 - 4ac) is sqrt(-7), or (sqrt7)i.

16 years ago

correct.

16 years ago

OK. x^2 + x - 6: Start with (x )(x ) We have to figure out 2 numbers when MULTIPLIED by each other gives -6, and when ADDED together gives 1. can you figure out these?

16 years ago

how about 3 and -2? So you have (x+3)(x-2) = 0

16 years ago

The first is correct. 2. Should be 4x + (y/4) = 42 3x - (y/2) = 26 3 and 4 are also incorrect. For #3, they tell us that 5 times the length eauals 12 times the width. that translates to 5x = 12y. Can you get the second equation? (remember the perimeter is...

16 years ago

yes, that is right..2x + 2y = 112. And, yes the first equation for #4 is x + y = 110. For the second equation...remember, it is 10 years ago...we have to take 10 off each of their ages...(x-10) - (y-10) = 10. Do you understand? 9

16 years ago

You are correct...it is all the above...promiscuity and early sexually active behavior are risk factors for cervical cancer

16 years ago

you're welcome!

16 years ago

you are correct. Genetics plays a strong role in alcoholism

16 years ago

Yes, you need the equation. The one you wrote is a start, but you need to BALAMCE it. Do you know how to do that?

16 years ago

The way you have it written the oxygens do not balance. It is actually: 4Fe + 3O2 > 2Fe2O3. (or, 2Fe + 1.5O2 > Fe2O3. So, basically 2 moles of Fe goes to form one mole of Fe2O3. Then, you must calculate how many moles of Fe you start with, and then you kn...

16 years ago

Woops, sorry Marissa for the delay; just saw your question! Remember, Sn1 reactions are based on the stability of the carbocations formed in the intermediate step. And Sn2 is favored if the carbocation formed is very unstable, thus it occurs in 1 step, wi...

16 years ago

Start with the equation of circumference of a circle: c = pi x d. The diamter is 2 x radius. So, the diameter of the first cirlce is 18cm. You know the diameter of the second circle. So, how do the circumferences compare?

16 years ago

Use interest = principle x rate x time. I'm not sure what you mean by "base." Principle here is $500, rate is 1.5%, and interest is $3.75. Can you solve it from here?

16 years ago

y = mx + b, and you're right, we do not know the y-intercept here. so, y = (2/5)x + b. They tell us the X-intercept is 4.5. How does this help us? The x-intercept is where it crosses the x-axis. At that point, y = 0. So, the line crosses the point (4.5,0)...

16 years ago

e- simpley stands for electron, and e-s for electrons (plural)

16 years ago

you're welcome!

16 years ago

you can use: (vf)^2 = (v0)^ + 2as where vf is "final velocity" v0 is "initial velocity" a is acceleration and s is distance

16 years ago

wait...if this is conservation of energy, better to use: convert the potential energy into kinetic energy! (sorry). potential energy is mgh, and kinetic enery is (1/2)m*v^2

16 years ago

yes, if the initial velocity is squred

16 years ago

So, it depends on what you're currently studying. If you're studying equations of motion, then use my first suggestion, but if you're studying conservation of energy, use mgh = (1/2)m*v^2. The m's cancel out: So, gh = v^2/2. You can solve for v, the veloc...

16 years ago

Divide the mass of the sun by the mass of saturn. (1.998 x 10^27)/(5.688 x 10^23). What do you get when you do this on your calculator?

16 years ago

Avogadro's number is the number particles of substance in one mole of that subtance. Or, to state it the oppsosite way: One mole of a substance contains Avogadro's constant number of particles of that substance.

16 years ago

Try to specific and tell us what exactly you do not understand

16 years ago

You should be ADDING the 2 equations...so it should be 12x = 132, instead of 2x = 132

16 years ago

Pull a 2 out first... 2(a^2 - 8ab + 32b^2) That should get you started

16 years ago

When you have en exponent...in this case x is raisid to the -3 power, and that is raised to another power, you MULTIPLY the exponents...so, this would be x raised to the -6 power.

16 years ago

It's hard to tell the way you wrote it...it looks like x raised to the 2 power times y raised to the 6 power...then there's a -3 in there...where does the -3 come in? is that an exponent?

16 years ago

If you subtract the second equation from the first, the a's cancel out. then you get 4b = -2. Can you do the rest?

16 years ago

This is "zinc 67"

16 years ago

The y-intercept is where it crosses the x-axis (where x = 0). So, just set x to be 0 and solve for y, and that gives you your y intercept. the same is true for the x-intercept (where y = 0)

16 years ago

no, it is not. The ordered pair (1,19) does not satisfy the first equation, because y must be less than or equal to 7x-13. If x = 1, then y cannot be 19.

16 years ago

subtract 3t^2 - 1 from both sides, and you get 4t^2 - 4t + 1 = 0. Then factor. Can you do that?

16 years ago

If you have to factor this, start with: (w )(w ) Then you need two factors that when ADDED together gives you -11, and when multiplied together gives you 30. Can you come up with these factors?

16 years ago

The child is going from a speed of 112 mi/h to a speed of 0 in .12 seconds...so their is a deceleration...Does this help?

15 years ago