# Complex Proportions

In this video we will be learning how to solve complex proportions (variables on both sides) using cross-multiplication.

For Example:

$\frac{x}{20}=\frac{(x+1)}{30}\leftarrow$ First we cross-multiply

$30x=20(x+1)\leftarrow$ Then we distribute the 20 to the x and 1

$30x-20x=20x +20-20x\leftarrow$ Subtract 20x from both sides to isolate x

$\frac{10x}{10}=\frac{20}{10}\leftarrow$ Divide by 10 on both sides

$x=2$
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Used by students across the country. Pre-Algebra, Algebra I, Geometry, & Algebra II