Cross multiplying is a way to solve an equation that involves a variable as part of two fractions set equal to each other. The variable is a placeholder for an unknown number or quantity, and cross-multiplying reduces the proportion to one simple equation, allowing you to solve for the variable in question. Cross multiplying is especially useful when you’re trying to solve a ratio. Here’s how to do it:
Cross Multiplying with a Single Variable
Set the two products equal to each other. Just set 26 equal to 10x.
26 = 10x.
It doesn’t matter which number you list first; since they’re equal, you can swap them from one side of the equation to the other with impunity, as long as you treat each term as a whole.
- So, if you’re trying to solve 2/x = 10/13 for x, you’d have 2 * 13 = x * 10, or 26 = 10x.