4x^2-21-18=0

Solution for 4x^2-21-18=0 equation:

Simplifying
4x2 + -21 + -18 = 0

Reorder the terms:
-21 + -18 + 4x2 = 0

Combine like terms: -21 + -18 = -39
-39 + 4x2 = 0

Solving
-39 + 4x2 = 0

Solving for variable 'x'.

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

Add '39' to each side of the equation.
-39 + 39 + 4x2 = 0 + 39

Combine like terms: -39 + 39 = 0
0 + 4x2 = 0 + 39
4x2 = 0 + 39

Combine like terms: 0 + 39 = 39
4x2 = 39

Divide each side by '4'.
x2 = 9.75

Simplifying
x2 = 9.75

Take the square root of each side:
x = {-3.122498999, 3.122498999}