9-(-11)=x

Solution for 9-(-11)=x equation:

Simplifying
9 + -1(-11) = x

Multiply -1 * -11
9 + 11 = x

Combine like terms: 9 + 11 = 20
20 = x

Solving
20 = x

Solving for variable 'x'.

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

Add '-1x' to each side of the equation.
20 + -1x = x + -1x

Combine like terms: x + -1x = 0
20 + -1x = 0

Add '-20' to each side of the equation.
20 + -20 + -1x = 0 + -20

Combine like terms: 20 + -20 = 0
0 + -1x = 0 + -20
-1x = 0 + -20

Combine like terms: 0 + -20 = -20
-1x = -20

Divide each side by '-1'.
x = 20

Simplifying
x = 20