Question

Fill in the blank with a constant, so that the resulting quadratic expression is the square of a binomial.

\[x^2 + 22x + \underline{~~~~}.\]

Answer 1

Answer: 121

Explanation:

The formula for the square of sums is
`(a+b)^2=a^2+2ab+b^2`.

Applying the formula, we see that the only option for b is 11 squared, or 121.

Answer 2

121.

Check: x^2+22x+121=(x+11)^2