Answer
$9z^{2}+48z+64$
Work Step by Step
From Page 302, we know that the square of a binomial sum $x+y$ is given by the following equation:
$(x+y)^{2}=x^{2}+2xy+y^{2}$
Therefore, $(3z+8)^{2}=(3z)^{2}+2(3z)(8)+8^{2}=3^{2}z^{2}+48z+64=9z^{2}+48z+64$.
