Solve r:20=5:x

$$r : 20 = 5 : x$$

Solve for r

$$r=\frac{100}{x}$$

$$x\neq 0$$

Steps for Solving Linear Equation

Multiply both sides of the equation by 20x, the least common multiple of 20,x.

$$xr=20\times 5$$

Multiply 20 and 5 to get 100.

$$xr=100$$

Divide both sides by x.

$$\frac{xr}{x}=\frac{100}{x}$$

Dividing by x undoes the multiplication by x.

$$r=\frac{100}{x}$$

Solve for x

$$x=\frac{100}{r}$$

$$r\neq 0$$

Steps for Solving Linear Equation

Variable x cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by 20x, the least common multiple of 20,x.

$$xr=20\times 5$$

Multiply 20 and 5 to get 100.

$$xr=100$$

The equation is in standard form.

$$rx=100$$

Divide both sides by r.

$$\frac{rx}{r}=\frac{100}{r}$$

Dividing by r undoes the multiplication by r.

$$x=\frac{100}{r}$$

Variable x cannot be equal to 0.

$$x=\frac{100}{r}\text{, }x\neq 0$$