If the difference of a number and 4 is multiplied by 3 the result is 19 The phrase a number means an arbitrary variable, let's call it x: x The difference of a number and 4: x - 4 The phrase is multiplied by means we multiply x - 4 by 3: 3(x - 4) The phrase the result is means equals, so we set 3(x - 4) equal to 19 3(x - 4) = 19