Answer
a. $n^{2}-14n+49$
b. $4x^{2}+36x+81$
Work Step by Step
a. $(n-7)^{2}$
...square the binomial.
$=n^{2}-2n(7)+7^{2}$
...simplify.
$=n^{2}-14n+49$
b. $(2x+9)^{2}$
...square the binomial.
$=(2x)^{2}+2(2x)(9)+9^{2}$
...simplify.
$=4x^{2}+36x+81$
