The Square of a positive integer is equal to the sum of the integer and 12. Find the integer Let the integer be x. The sum of the integer and 12 is written as x + 12. The square of a positive integer is written as x^2. We set these equal to each other: x^2 = x + 12 Subtract x + 12 from each side: x^2 - x - 12 = 0 We have a quadratic function. Run it through our search engine and we get x = 3 and x = -4. The problem asks for a positive integer, so we have x = 3