the difference of twice a number and 8 is at most -30. The phrase a number means an arbitrary variable, let's call it x. Twice this number means we multiply by 2, so we have 2x. We take the difference of 2x and 8, meaning we subtract 8: 2x - 8 Finally, the phrase at most means an inequality, also known as less than or equal to: 2x - 8 <= 30 <-- This is our algebraic expression To solve this, we type it into the search engine and get x <= 19.