Question

HELP PLEEEASE!!!!!!! FOR A MEDAL!!!!!!!!!!!!
Solve the following system of equations.
-3x-4y=20
-4x-3y=15

Answer 1

multiply the top equation by 4 and the bottom equation by 3. You will have -12x in both equations. Then add the two equations and the -12x will cancel out, leaving you with -25y = 125, y=-5. Therefore x=0

Answer 2

ok so u need to make one of the variables in both equations cancel out

Answer 3

Now what if we decided to simply multiply both sides of the second equation by -1:

Then we would have

-3x - 4y = 20
4x + 3y = -15

And after combining the equations together we would have
x - y = 5

And upon isolating x:
x = 5 + y

We could then substitute that into the second equation:
4(5 + y) + 3y = -15
20 + 4y + 3y = -15
20 + 7y = -15
7y = -35
y = -5

And upon back substituting we would solve for x:
4x + 3(-5) = -15
4x - 15 = -15
4x = 15 - 15
4x = 0
x = 0