Solve for a a/5=b+3a

$\frac{a}{5} = b + 3 a$

Multiply both sides by $5$ .

$\frac{a}{5} \cdot 5 = (b + 3 a) \cdot 5$

Simplify.

Simplify the left side.

Cancel the common factor of $5$ .

Cancel the common factor.

$\frac{a}{5} \cdot 5 = (b + 3 a) \cdot 5$

Rewrite the expression.

$a = (b + 3 a) \cdot 5$

Simplify the right side.

Simplify $(b + 3 a) \cdot 5$ .

Apply the distributive property.

$a = b \cdot 5 + 3 a \cdot 5$

Simplify the expression.

Move $5$ to the left of $b$ .

$a = 5 \cdot b + 3 a \cdot 5$

Multiply $5$ by $3$ .

$a = 5 \cdot b + 15 a$

Reorder $5 b$ and $15 a$ .

$a = 15 a + 5 b$

Solve for $a$ .

Move all terms containing $a$ to the left side of the equation.

Subtract $15 a$ from both sides of the equation.

$a - 15 a = 5 b$

Subtract $15 a$ from $a$ .

$- 14 a = 5 b$

Divide each term in $- 14 a = 5 b$ by $- 14$ and simplify.

Divide each term in $- 14 a = 5 b$ by $- 14$ .

$\frac{- 14 a}{- 14} = \frac{5 b}{- 14}$

Simplify the left side.

Cancel the common factor of $- 14$ .

Cancel the common factor.

$\frac{- 14 a}{- 14} = \frac{5 b}{- 14}$

Divide $a$ by $1$ .

$a = \frac{5 b}{- 14}$

Simplify the right side.

Move the negative in front of the fraction.

$a = - \frac{5 b}{14}$