91=4x(x)

Solution for 91=4x(x) equation:

Simplifying
91 = 4x(x)

Multiply x * x
91 = 4x2

Solving
91 = 4x2

Solving for variable 'x'.

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

Add '-4x2' to each side of the equation.
91 + -4x2 = 4x2 + -4x2

Combine like terms: 4x2 + -4x2 = 0
91 + -4x2 = 0

Add '-91' to each side of the equation.
91 + -91 + -4x2 = 0 + -91

Combine like terms: 91 + -91 = 0
0 + -4x2 = 0 + -91
-4x2 = 0 + -91

Combine like terms: 0 + -91 = -91
-4x2 = -91

Divide each side by '-4'.
x2 = 22.75

Simplifying
x2 = 22.75

Take the square root of each side:
x = {-4.769696007, 4.769696007}