15-X^2-6=0

Solution for 15-X^2-6=0 equation:

Simplifying
15 + -1X2 + -6 = 0

Reorder the terms:
15 + -6 + -1X2 = 0

Combine like terms: 15 + -6 = 9
9 + -1X2 = 0

Solving
9 + -1X2 = 0

Solving for variable 'X'.

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

Add '-9' to each side of the equation.
9 + -9 + -1X2 = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1X2 = 0 + -9
-1X2 = 0 + -9

Combine like terms: 0 + -9 = -9
-1X2 = -9

Divide each side by '-1'.
X2 = 9

Simplifying
X2 = 9

Take the square root of each side:
X = {-3, 3}