Solving Multi-Step Equations With Parentheses
If an equation you encounter contains parentheses, you’ll need to clear them from the equations before attempting to combine like terms. To clear parentheses from an equation, use the distributive property to multiply the number in front of the parentheses by each term inside of the parentheses. If the number in front of the parentheses is negative, multiply the negative against each term inside the parentheses.
The Distributive Property of Multiplication
For all real numbers [latex]a, b[/latex] and [latex]c[/latex], [latex]a(b+c)=ab+ac[/latex].
What this means is that when a number multiplies an expression inside parentheses, you can distribute the multiplication to each term of the expression individually. Then, you can follow the steps we have already practiced to isolate the variable and solve the equation.
In the next example, there are parentheses on both sides of the equal sign. To clear them, you’ll need to use the distributive property on both sides of the equation.
Clearing Fractions and Decimals from Equations
Sometimes, you will encounter a multi-step equation containing fractions. Before attempting to solve the equation, first use the multiplication property of equality to multiply both sides of the equation by a common denominator of all of the fractions in the equation. This will clear all the fractions out of the equation. It is acceptable to simply do the operations on the fractions without clearing them first, but the technique used here will apply to more complicated situations you’ll encounter later, so it is worthwhile to practice it. Regardless of which method you use to solve equations containing variables, you will get the same answer. You can choose the method you find the easiest. Remember to check your answer by substituting your solution into the original equation.
Sometimes, you will encounter a multi-step equation with decimals. To clear the decimals from the equation, use the multiplication property of equality to multiply both sides of the equation by a factor of [latex]10[/latex], that will help clear the decimals.