Answer
a. $(x+3)^{2}$
b. $(x-7)^{2}$
Work Step by Step
a.
$x^{2}+6x+9=$
...write the last term as a square.
$=x^{2}+6x+3^{2}$
...does middle term equal $2ab$?
$6x=2(x)(3)$
$=x^{2}+2(x)(3)+3^{2}$
...write as the square of a binomial.
$=(x+3)^{2}$
b.
$x^{2}-14x+49=$
...write the last term as a square.
$=x^{2}-14x+7^{2}$
...does middle term equal $2ab$?
$14x=2(x)(7)$
$=x^{2}-2(x)(7)+7^{2}$
...write as the square of a binomial.
$=(x-7)^{2}$
