7x^2+x^2-18=0

Solution for 7x^2+x^2-18=0 equation:

Simplifying
7x2 + x2 + -18 = 0

Reorder the terms:
-18 + 7x2 + x2 = 0

Combine like terms: 7x2 + x2 = 8x2
-18 + 8x2 = 0

Solving
-18 + 8x2 = 0

Solving for variable 'x'.

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

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

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

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

Divide each side by '8'.
x2 = 2.25

Simplifying
x2 = 2.25

Take the square root of each side:
x = {-1.5, 1.5}