SOLUTION: solve system by elimination -4x+5y=1 4x-4y=-4 the correct answer is (-4,-3) I dont understand elimination method

Algebra ->  Graphs -> SOLUTION: solve system by elimination -4x+5y=1 4x-4y=-4 the correct answer is (-4,-3) I dont understand elimination method       Log On


   

Question 723190: solve system by elimination
-4x+5y=1
4x-4y=-4
the correct answer is (-4,-3) I dont understand elimination method
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

-4x%2B5y=1
4x-4y=-4
___________________add them, -4x and 4x will cancel each other; so, we will eliminate variable x and solve for y
-4x%2B5y%2B4x-4y=1%2B%28-4%29
cross%28-4x%29%2B5y%2Bcross%284x%29-4y=1-4
5y-4y=-3
highlight%28y=-3%29
now go one of given equations, plug in y value and solve for x

4x-4%28-3%29=-4
4x%2B12=-4
4x=-4-12
4x=-16
x=-16%2F4
highlight%28x=-4%29