91=(2x-2)(x+1)

Solution for 91=(2x-2)(x+1) equation:

Simplifying
91 = (2x + -2)(x + 1)

Reorder the terms:
91 = (-2 + 2x)(x + 1)

Reorder the terms:
91 = (-2 + 2x)(1 + x)

Multiply (-2 + 2x) * (1 + x)
91 = (-2(1 + x) + 2x * (1 + x))
91 = ((1 * -2 + x * -2) + 2x * (1 + x))
91 = ((-2 + -2x) + 2x * (1 + x))
91 = (-2 + -2x + (1 * 2x + x * 2x))
91 = (-2 + -2x + (2x + 2x2))

Combine like terms: -2x + 2x = 0
91 = (-2 + 0 + 2x2)
91 = (-2 + 2x2)

Solving
91 = -2 + 2x2

Solving for variable 'x'.

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

Add '-2x2' to each side of the equation.
91 + -2x2 = -2 + 2x2 + -2x2

Combine like terms: 2x2 + -2x2 = 0
91 + -2x2 = -2 + 0
91 + -2x2 = -2

Add '-91' to each side of the equation.
91 + -91 + -2x2 = -2 + -91

Combine like terms: 91 + -91 = 0
0 + -2x2 = -2 + -91
-2x2 = -2 + -91

Combine like terms: -2 + -91 = -93
-2x2 = -93

Divide each side by '-2'.
x2 = 46.5

Simplifying
x2 = 46.5

Take the square root of each side:
x = {-6.819090848, 6.819090848}