21(-2)=x

Solution for 21(-2)=x equation:

Simplifying
21(-2) = x

Multiply 21 * -2
-42 = x

Solving
-42 = 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.
-42 + -1x = x + -1x

Combine like terms: x + -1x = 0
-42 + -1x = 0

Add '42' to each side of the equation.
-42 + 42 + -1x = 0 + 42

Combine like terms: -42 + 42 = 0
0 + -1x = 0 + 42
-1x = 0 + 42

Combine like terms: 0 + 42 = 42
-1x = 42

Divide each side by '-1'.
x = -42

Simplifying
x = -42