Solve for a 4(a+3)-2(a+6)=20

$4 (a + 3) - 2 (a + 6) = 20$

Simplify $4 (a + 3) - 2 (a + 6)$ .

Simplify each term.

Apply the distributive property.

$4 a + 4 \cdot 3 - 2 (a + 6) = 20$

Multiply $4$ by $3$ .

$4 a + 12 - 2 (a + 6) = 20$

Apply the distributive property.

$4 a + 12 - 2 a - 2 \cdot 6 = 20$

Multiply $- 2$ by $6$ .

$4 a + 12 - 2 a - 12 = 20$

Simplify by adding terms.

Combine the opposite terms in $4 a + 12 - 2 a - 12$ .

Subtract $12$ from $12$ .

$4 a - 2 a + 0 = 20$

Add $4 a - 2 a$ and $0$ .

$4 a - 2 a = 20$

Subtract $2 a$ from $4 a$ .

$2 a = 20$

Divide each term in $2 a = 20$ by $2$ and simplify.

Divide each term in $2 a = 20$ by $2$ .

$\frac{2 a}{2} = \frac{20}{2}$

Simplify the left side.

Cancel the common factor of $2$ .

Cancel the common factor.

$\frac{2 a}{2} = \frac{20}{2}$

Divide $a$ by $1$ .

$a = \frac{20}{2}$

Simplify the right side.

Divide $20$ by $2$ .

$a = 10$