the sum of 6 and 7, plus 5 times a number, is -12 The sum of 6 and 7 means we add the two numbers: 6 + 7 This evaluates to 13 Next, we take 5 times a number. The phrase a number means an arbitrary variable, let's call it x. So we multiply x by 5: 5x The first two words say the sum, so we add 13 and 5x 13 + 5x The word is means an equation, so we set 13 + 5x equal to -12 13 + 5x = -12 <-- This is our algebraic expression If the problem asks you to take it a step further and solve for x, then you type this algebraic expression into our search engine and you get: x = -5