-g^2-g=-90

Solution for -g^2-g=-90 equation:

Simplifying
-1g2 + -1g = -90

Reorder the terms:
-1g + -1g2 = -90

Solving
-1g + -1g2 = -90

Solving for variable 'g'.

Reorder the terms:
90 + -1g + -1g2 = -90 + 90

Combine like terms: -90 + 90 = 0
90 + -1g + -1g2 = 0

Factor a trinomial.
(9 + -1g)(10 + g) = 0

Subproblem 1
Set the factor '(9 + -1g)' equal to zero and attempt to solve:

Simplifying
9 + -1g = 0

Solving
9 + -1g = 0

Move all terms containing g to the left, all other terms to the right.

Add '-9' to each side of the equation.
9 + -9 + -1g = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1g = 0 + -9
-1g = 0 + -9

Combine like terms: 0 + -9 = -9
-1g = -9

Divide each side by '-1'.
g = 9

Simplifying
g = 9
Subproblem 2
Set the factor '(10 + g)' equal to zero and attempt to solve:

Simplifying
10 + g = 0

Solving
10 + g = 0

Move all terms containing g to the left, all other terms to the right.

Add '-10' to each side of the equation.
10 + -10 + g = 0 + -10

Combine like terms: 10 + -10 = 0
0 + g = 0 + -10
g = 0 + -10

Combine like terms: 0 + -10 = -10
g = -10

Simplifying
g = -10
Solution
g = {9, -10}