x*x-15=21

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Solution for x*x-15=21 equation: 


Simplifying
x * x + -15 = 21

Multiply x * x
x2 + -15 = 21

Reorder the terms:
-15 + x2 = 21

Solving
-15 + x2 = 21

Solving for variable 'x'.

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

Add '15' to each side of the equation.
-15 + 15 + x2 = 21 + 15

Combine like terms: -15 + 15 = 0
0 + x2 = 21 + 15
x2 = 21 + 15

Combine like terms: 21 + 15 = 36
x2 = 36

Simplifying
x2 = 36

Take the square root of each side:
x = {-6, 6}

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