21x^2-6=15

Solution for 21x^2-6=15 equation:

Simplifying
21x2 + -6 = 15

Reorder the terms:
-6 + 21x2 = 15

Solving
-6 + 21x2 = 15

Solving for variable 'x'.

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

Add '6' to each side of the equation.
-6 + 6 + 21x2 = 15 + 6

Combine like terms: -6 + 6 = 0
0 + 21x2 = 15 + 6
21x2 = 15 + 6

Combine like terms: 15 + 6 = 21
21x2 = 21

Divide each side by '21'.
x2 = 1

Simplifying
x2 = 1

Take the square root of each side:
x = {-1, 1}