4x^2 + 5x - 8 + (- 4x^2 - 5x + 8) = 0
all ur doing is changing the signs so they will cancel each other out.
so ur adding : -4x^2 - 5x + 8
The answer is in the picture
Its just like using your hand only difference is a ruler unless its a point in it it goes into segments like quarters etc.
