X^2-16X-87=-7

Solution for X^2-16X-87=-7 equation:

Simplifying
X2 + -16X + -87 = -7

Reorder the terms:
-87 + -16X + X2 = -7

Solving
-87 + -16X + X2 = -7

Solving for variable 'X'.

Reorder the terms:
-87 + 7 + -16X + X2 = -7 + 7

Combine like terms: -87 + 7 = -80
-80 + -16X + X2 = -7 + 7

Combine like terms: -7 + 7 = 0
-80 + -16X + X2 = 0

Factor a trinomial.
(-4 + -1X)(20 + -1X) = 0

Subproblem 1
Set the factor '(-4 + -1X)' equal to zero and attempt to solve:

Simplifying
-4 + -1X = 0

Solving
-4 + -1X = 0

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

Add '4' to each side of the equation.
-4 + 4 + -1X = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -1X = 0 + 4
-1X = 0 + 4

Combine like terms: 0 + 4 = 4
-1X = 4

Divide each side by '-1'.
X = -4

Simplifying
X = -4
Subproblem 2
Set the factor '(20 + -1X)' equal to zero and attempt to solve:

Simplifying
20 + -1X = 0

Solving
20 + -1X = 0

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

Add '-20' to each side of the equation.
20 + -20 + -1X = 0 + -20

Combine like terms: 20 + -20 = 0
0 + -1X = 0 + -20
-1X = 0 + -20

Combine like terms: 0 + -20 = -20
-1X = -20

Divide each side by '-1'.
X = 20

Simplifying
X = 20
Solution
X = {-4, 20}