-X^2+X+90=

Solution for -X^2+X+90= equation:

Simplifying
-1X2 + X + 90 = 0

Reorder the terms:
90 + X + -1X2 = 0

Solving
90 + X + -1X2 = 0

Solving for variable 'X'.

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

Subproblem 1
Set the factor '(10 + -1X)' equal to zero and attempt to solve:

Simplifying
10 + -1X = 0

Solving
10 + -1X = 0

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

Add '-10' to each side of the equation.
10 + -10 + -1X = 0 + -10

Combine like terms: 10 + -10 = 0
0 + -1X = 0 + -10
-1X = 0 + -10

Combine like terms: 0 + -10 = -10
-1X = -10

Divide each side by '-1'.
X = 10

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

Simplifying
9 + X = 0

Solving
9 + X = 0

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

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

Combine like terms: 9 + -9 = 0
0 + X = 0 + -9
X = 0 + -9

Combine like terms: 0 + -9 = -9
X = -9

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