H(-2)=-x^2-5x

Solution for H(-2)=-x^2-5x equation:

(-2)=-H^2-5H

We move all terms to the left:

(-2)-(-H^2-5H)=0

We add all the numbers together, and all the variables

-(-H^2-5H)-2=0

We get rid of parentheses

H^2+5H-2=0

a = 1; b = 5; c = -2;
Δ = b2-4ac
Δ = 52-4·1·(-2)
Δ = 33
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$H_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-\sqrt{33}}{2*1}=\frac{-5-\sqrt{33}}{2}
$
$H_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{33}}{2*1}=\frac{-5+\sqrt{33}}{2}
$