Question

What is the solution? use elimination .
4x-y=23
7x-y=21
PLEASE HELPPP!!!!

Answer 1

just subtract one from the other to eliminate y:

-3x = 2
Now you can get x, and then plug that in to get y.

Answer 2

I don't understand?

Answer 3

Where did you get -3x=2??

Answer 4

elimination means that you manipulate the equations so that one of the variables is eliminated.

Since the left sides are equal to the right sides, subtracting the left sides from each other and the right sides from each other gives a valid equation.

You can see that if you subtract -y from -y, the result is zero. 4x-7x = -3x, so you are left with

-3x + 0y = 2

Answer 5

clearly you need to review the material on elimination. Google will provide lots of examples.

Answer 6

So what do we do to find the equation out ?
-3x+0y=2
the answer chosies they gave me are-
a.(11,0)
b.(4,-7)
c.(11,44)
d.(4,7)

Answer 7

clearly there is a typo in the equations, or the answer key is wrong. The equations you gave have solution

x = -2/3
y = -77/3

which you can check by plugging those values into both equations.

(4,-7) is a solution to 4x-y=23

It is also a solution to 7x+y = 21, not the equation you gave.

Be more careful with your postings.

Answer 8

So the answer i got from that is (4,-7) correct??

Answer 9

So, with the correct equations, you'd have to add them to eliminate y:

4x-y=23
7x+y=21
-------------
11x=44
x=4

then plug that into either equation to figure out y.

Answer 10

so, 7 and idk the other one ??

Answer 11

so is it (11,44)??? @steve ??

Answer 12

NOOO

It's (4,-7)!

I explained how that pair fits both equations.

try plugging in your numbers and see that they are waaaaaayyyy off!