Solving for a Variable
Combining Variables
In solving equations in the form ax + c = bx + d the goal remains to rewrite the equation in the form variable = constant. Begin by combining like terms so there is only one variable term and one constant term.
Example 6 Solve 5x + 7x = 72
Step 1. Combine like terms.
5x + 7x = 72
12x = 72
Step 2. Divide both sides of the resulting equation by 12 and simplify.
12x= 72
12 12
x = 6
Step 3. Check the solution.
5?6 + 7?6 = 72
30 + 42 = 72
72 = 72