What number can be placed in the box, so that the resulting quadratic expression is the square of a binomial?
\(x^2 + 22x + \boxed{\phantom{000}}.\)
The number that goes in the box is 22^2 = 484.
If the coefficient of the first term is 1: to find the last term, divide the middle term by 2, and square the result.
22 / 2 = 11 ---> 112 = 121
x2 + 22x + 121 ---> (x + 11)2
+185 
