18x^2+13-21=0

Solution for 18x^2+13-21=0 equation:

Simplifying
18x2 + 13 + -21 = 0

Reorder the terms:
13 + -21 + 18x2 = 0

Combine like terms: 13 + -21 = -8
-8 + 18x2 = 0

Solving
-8 + 18x2 = 0

Solving for variable 'x'.

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

Add '8' to each side of the equation.
-8 + 8 + 18x2 = 0 + 8

Combine like terms: -8 + 8 = 0
0 + 18x2 = 0 + 8
18x2 = 0 + 8

Combine like terms: 0 + 8 = 8
18x2 = 8

Divide each side by '18'.
x2 = 0.4444444444

Simplifying
x2 = 0.4444444444

Take the square root of each side:
x = {-0.666666667, 0.666666667}