User:Compnerd~enwiki

Hola mi amigos. Mi llamo Drew.

I don't actually speak Spanish.

Problem 81: $y=-x^{2}+x-2$

Formula to use

${\frac {[(-(x+h)^{2})+(x+h)-2]-[-x^{2}+x-2]}{h}}$

Distribute -1 in original formula

${\frac {[(-(x+h)^{2})+(x+h)-2]+[x^{2}-x+2]}{h}}$

Square the new formula

${\frac {[(-(x^{2}+2xh+h^{2}))+x+h-2]+[x^{2}-x+2]}{h}}$

Negate new formula

${\frac {[(-x^{2}-2xh-h^{2})+x+h-2]+[x^{2}-x+2]}{h}}$

Change format

${\frac {[-x^{2}-2xh-h^{2}+x+h-2]+[x^{2}-x+2]}{h}}$

Change format

${\frac {-x^{2}-2xh-h^{2}+x+h-2+x^{2}-x+2}{h}}$

Organize to cancel out

${\frac {-x^{2}+x^{2}-2xh-h^{2}+h+x-x-2+2}{h}}$

Cancel items

${\frac {-2xh-h^{2}+h}{h}}$

Difference formula:

$2x-h+1$