13) First, take the constant (number that is not a variable. In this case -59) and use arithmatic to bring it to the other side. So we have n^2 + 14n = 51
Then to complete the square, we have to do a quick computation. Take the coefficient with the single variable, not the squared variable (in this case 14) and divide it by 2, (getting seven). Now, square that answer, seven, leaving us with 49. Add that to the end of the equation as the coefficient, but remember to add it to the other side of the equation too, following the math rules. So now we have n^2 + 14n + 49 = 100. Now, we can factor the left side to be (n+7) * (n+7), or (n+7)^2. Now our equation is (n+7)^2 = 100. We can take the square root of both sides, giving us: n + 7 = -10 and n +7 = 10 (because when you take the square root of a number, it could be positive or negative. Now solve those two equations for n and you have your answer: n = -17 and n=3
Sorry this was such a long, confsing answer. It's really not as hard as it seems, I just wanted to kind of explain how to do it.
