(x-4)(x+4)=15x

Solution for (x-4)(x+4)=15x equation:

Simplifying
(x + -4)(x + 4) = 15x

Reorder the terms:
(-4 + x)(x + 4) = 15x

Reorder the terms:
(-4 + x)(4 + x) = 15x

Multiply (-4 + x) * (4 + x)
(-4(4 + x) + x(4 + x)) = 15x
((4 * -4 + x * -4) + x(4 + x)) = 15x
((-16 + -4x) + x(4 + x)) = 15x
(-16 + -4x + (4 * x + x * x)) = 15x
(-16 + -4x + (4x + x2)) = 15x

Combine like terms: -4x + 4x = 0
(-16 + 0 + x2) = 15x
(-16 + x2) = 15x

Solving
-16 + x2 = 15x

Solving for variable 'x'.

Reorder the terms:
-16 + -15x + x2 = 15x + -15x

Combine like terms: 15x + -15x = 0
-16 + -15x + x2 = 0

Factor a trinomial.
(-1 + -1x)(16 + -1x) = 0

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

Simplifying
-1 + -1x = 0

Solving
-1 + -1x = 0

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

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

Combine like terms: -1 + 1 = 0
0 + -1x = 0 + 1
-1x = 0 + 1

Combine like terms: 0 + 1 = 1
-1x = 1

Divide each side by '-1'.
x = -1

Simplifying
x = -1
Subproblem 2
Set the factor '(16 + -1x)' equal to zero and attempt to solve:

Simplifying
16 + -1x = 0

Solving
16 + -1x = 0

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

Add '-16' to each side of the equation.
16 + -16 + -1x = 0 + -16

Combine like terms: 16 + -16 = 0
0 + -1x = 0 + -16
-1x = 0 + -16

Combine like terms: 0 + -16 = -16
-1x = -16

Divide each side by '-1'.
x = 16

Simplifying
x = 16
Solution
x = {-1, 16}