Question

I need help on this math problem
Solve the systems of equations by elimination.
-2x+y=7
6x+12y=24

Answer 1

multiply the top equation by 3

-6x+3y=+21
6x+12y=24

add the equations
15y=45
solve for y. then put that y into either equation, and solve for x.

Answer 2

Can you help me with this problem.
Solve the equations by elimination
7x+3y=-1.5
2x-5y=-30.3

Answer 3

Multiply 1st equation by 5,
and the 2nd equation by 3.
Then add the two equations.

This will eliminate the y variable.

Take the value you get for x and substitute that value in either equation and solve for y.

Answer 4

helper can you show me the work because I did what you said and stll came up with the wrong answer.
Solve the systems equations by elimination.
7x+3y=-1.5
2x-5y=-30.3

Answer 5

5(7x + 3y = -1.5) = 35x + 15y = -7.5
3(2x - 5y = -30.3) = 6x - 15y = -90.9

35x + 15y = -7.5
6x - 15y = -90.9
Add two equations
41x + 0 = -98.4
41x = -98.4
x = -2.4

7x + 3y = -1.5
x = -2.4
7(-2.4) + 3y = -1.5
-16.8 + 3y = -1.5
3y = 15.3
y = 5.1

x = -2.4, y = 5.1

Answer 6

Thanks so much helped out a lot.
I got one question when both equations are subtraction do I leave them the same or switch them from subtraction to addition

Answer 7

You can leave the same and then subtract the equations.

I like to have one equation as addition (+)variables and one equation with negative variables. Then I can add the equation.

I know that I am less apt to make a mistake when adding equations as opposed to subtracting negative numbers.

Do what even is easiest for you.

Good luck. :)

Answer 8

One more problem... An orange contains 50 mg of calcium and 0.5 mg of iron. An apple contains 8 mg of calcium and 0.4 mg of iron. How many of each are required to obtain 151 mg of calcium and 2.55 mg of iron?