SOLUTION: You are working with your friend who finds the solution of `-x + 2y = 1` and `-2x - 3y = -12` to be `(-1,0)`. Explain to your friend why the answer is incorrect.

Algebra ->  Linear-equations -> SOLUTION: You are working with your friend who finds the solution of `-x + 2y = 1` and `-2x - 3y = -12` to be `(-1,0)`. Explain to your friend why the answer is incorrect.       Log On


   

Question 1191811: You are working with your friend who finds the solution of `-x + 2y = 1` and `-2x - 3y = -12` to be `(-1,0)`. Explain to your friend why the answer is incorrect.
Found 3 solutions by greenestamps, josgarithmetic, math_tutor2020:
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The point (x,y)=(-1,0) does not satisfy the second equation, -2x-3y=-12.

Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
No matter any explanation

system%28-x%2B2y=1%2C-2x-3y=-12%29

system%28-x%2B2y=1%2C2x%2B3y=12%29

system%28-2x%2B4y=2%2C2x%2B3y=12%29

Sum the two equations.
7y=12
highlight%28y=2%29
-
-x%2B2y=1
x-2y=-1
x=2y-1
x=2%2A2-1
highlight%28x=3%29

Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

Another viewpoint:

If you graphed the two equations (using your favorite graphing tool), then this is what it looks like

I used GeoGebra to graph this.

The two lines cross at (x,y) = (3,2) which is the solution to the system.
Plug those coordinates back into the original equations and simplify.
You should get the same thing on both sides to verify the solution.