Solve A=1/l(b+c)h

$$A = \frac { 1 } { l } ( b + c ) h$$

Solve for b

$$\left\{\begin{matrix}b=\frac{Al}{h}-c\text{, }&l\neq 0\text{ and }h\neq 0\\b\in \mathrm{R}\text{, }&A=0\text{ and }h=0\text{ and }l\neq 0\end{matrix}\right.$$

Steps for Solving Linear Equation

Multiply both sides of the equation by l.

$$Al=1\left(b+c\right)h$$

Use the distributive property to multiply 1 by b+c.

$$Al=\left(b+c\right)h$$

Use the distributive property to multiply b+c by h.

$$Al=bh+ch$$

Swap sides so that all variable terms are on the left hand side.

$$bh+ch=Al$$

Subtract ch from both sides.

$$bh=Al-ch$$

The equation is in standard form.

$$hb=Al-ch$$

Divide both sides by h.

$$\frac{hb}{h}=\frac{Al-ch}{h}$$

Dividing by h undoes the multiplication by h.

$$b=\frac{Al-ch}{h}$$

Divide Al-ch by h.

$$b=\frac{Al}{h}-c$$

Solve for A

$$A=\frac{h\left(b+c\right)}{l}$$

$$l\neq 0$$