The sum of a number, n, and its square n^2 is 72. In equation form, this is n + n^2 = 72. Try making this into a polynomial equaling 0.
n + n^2 =72 subtract 72
n^2 + 1n -72 = 0 Now factor this polynomial
(n-8) (n+9) = 0 Solutions to this problem are 8 and -9
Plug in for n to check.
8 + 64 = 72 8 is correct
-9 + 81 = 72 -9 is also correct!!