Solve a=7(3b-c)/b

$$a = \frac { 7 ( 3 b - c ) } { b }$$

Solve for b

$$\left\{\begin{matrix}b=\frac{7c}{21-a}\text{, }&c\neq 0\text{ and }a\neq 21\\b\neq 0\text{, }&c=0\text{ and }a=21\end{matrix}\right.$$

Steps for Solving Linear Equation

Variable b cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by b.

$$ab=7\left(3b-c\right)$$

Use the distributive property to multiply 7 by 3b-c.

$$ab=21b-7c$$

Subtract 21b from both sides.

$$ab-21b=-7c$$

Combine all terms containing b.

$$\left(a-21\right)b=-7c$$

Divide both sides by a-21.

$$\frac{\left(a-21\right)b}{a-21}=-\frac{7c}{a-21}$$

Dividing by a-21 undoes the multiplication by a-21.

$$b=-\frac{7c}{a-21}$$

Variable b cannot be equal to 0.

$$b=-\frac{7c}{a-21}\text{, }b\neq 0$$

Solve for a

$$a=-\frac{7c}{b}+21$$

$$b\neq 0$$