3(10)-8(9)=x

Solution for 3(10)-8(9)=x equation:

Simplifying
3(10) + -8(9) = x

Multiply 3 * 10
30 + -8(9) = x

Multiply -8 * 9
30 + -72 = x

Combine like terms: 30 + -72 = -42
-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