9
 = 
x
x
1

Cross multiply:
9 * 1 = x * x

Simplifying
9 * 1 = x * x

Multiply 9 * 1
9 = x * x

Multiply x * x
9 = x2

Solving
9 = x2

Solving for variable 'x'.

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

Add '-1x2' to each side of the equation.
9 + -1x2 = x2 + -1x2

Combine like terms: x2 + -1x2 = 0
9 + -1x2 = 0

Add '-9' to each side of the equation.
9 + -9 + -1x2 = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1x2 = 0 + -9
-1x2 = 0 + -9

Combine like terms: 0 + -9 = -9
-1x2 = -9

Divide each side by '-1'.
x2 = 9

Simplifying
x2 = 9

Take the square root of each side:
x = {-3, 3}