5x^2-21+18=0

Solution for 5x^2-21+18=0 equation:

Simplifying
5x2 + -21 + 18 = 0

Reorder the terms:
-21 + 18 + 5x2 = 0

Combine like terms: -21 + 18 = -3
-3 + 5x2 = 0

Solving
-3 + 5x2 = 0

Solving for variable 'x'.

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

Add '3' to each side of the equation.
-3 + 3 + 5x2 = 0 + 3

Combine like terms: -3 + 3 = 0
0 + 5x2 = 0 + 3
5x2 = 0 + 3

Combine like terms: 0 + 3 = 3
5x2 = 3

Divide each side by '5'.
x2 = 0.6

Simplifying
x2 = 0.6

Take the square root of each side:
x = {-0.774596669, 0.774596669}