## Algebra 1: Common Core (15th Edition)

B. $71/15$
Recall, if terms are like terms, we can add or subtract these terms just like we add or subtract numbers. Thus, because 7p and 8p are like terms, we can add them to simplify the equation to $15p-12=59.$ In order to solve this algebraic equation, we must isolate the variable. A variable is the letter in the problem (for instance, in the equation x+2=10, x is the variable). Because addition and subtraction are inverse operations (they cancel each other out), we know we must add when a number is being subtracted from the variable and subtract when a number is being added to the variable. In the equation $15p-12=59$, we must get rid of the 12, which is on the same side as p, in order to solve. Thus, we add 12 on both sides of the equation to find that $15p=71$. We now divide by 15 to obtain that $p=71/15$.