15=x^2-1

Solution for 15=x^2-1 equation:

Simplifying
15 = x2 + -1

Reorder the terms:
15 = -1 + x2

Solving
15 = -1 + x2

Solving for variable 'x'.

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

Add '-1x2' to each side of the equation.
15 + -1x2 = -1 + x2 + -1x2

Combine like terms: x2 + -1x2 = 0
15 + -1x2 = -1 + 0
15 + -1x2 = -1

Add '-15' to each side of the equation.
15 + -15 + -1x2 = -1 + -15

Combine like terms: 15 + -15 = 0
0 + -1x2 = -1 + -15
-1x2 = -1 + -15

Combine like terms: -1 + -15 = -16
-1x2 = -16

Divide each side by '-1'.
x2 = 16

Simplifying
x2 = 16

Take the square root of each side:
x = {-4, 4}