Solve for: (30-(-9)) * 2=30 * 2+x * 2

Expression: $\left( 30-\left( -9 \right) \right) \times 2=30 \times 2+x \times 2$

When there is a $-$ in front of an expression in parentheses, change the sign of each term of the expression and remove the parentheses

$\left( 30+9 \right) \times 2=30 \times 2+x \times 2$

Multiply the numbers

$\left( 30+9 \right) \times 2=60+x \times 2$

Use the commutative property to reorder the terms

$\left( 30+9 \right) \times 2=60+2x$

Add the numbers

$39 \times 2=60+2x$

Multiply the numbers

$78=60+2x$

Move the variable to the left-hand side and change its sign

$78-2x=60$

Move the constant to the right-hand side and change its sign

$-2x=60-78$

Calculate the difference

$-2x=-18$

Divide both sides of the equation by $-2$

$x=9$