The square of a number increased by 7 is 23 The phrase a number means an arbitrary variable, let's call it x. x The square of a number means we raise x to the power of 2: x^2 Increased by means we add 7 to x^2 x^2 + 7 The word is means an equation. So we set x^2 + 7 equal to 23: x^2 + 7 = 23