x(x+x)=4(4+5)

Solution for x(x+x)=4(4+5) equation:

Simplifying
x(x + x) = 4(4 + 5)

Combine like terms: x + x = 2x
x(2x) = 4(4 + 5)

Remove parenthesis around (2x)
x * 2x = 4(4 + 5)

Reorder the terms for easier multiplication:
2x * x = 4(4 + 5)

Multiply x * x
2x2 = 4(4 + 5)

Combine like terms: 4 + 5 = 9
2x2 = 4(9)

Multiply 4 * 9
2x2 = 36

Solving
2x2 = 36

Solving for variable 'x'.

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

Divide each side by '2'.
x2 = 18

Simplifying
x2 = 18

Take the square root of each side:
x = {-4.242640687, 4.242640687}