Answer
$z=3$ and $z=-7$
Work Step by Step
$(z-3)(z+7)=0$ Original problem.
$(z-3)=0$ and $(z+7)=0$ Set both factors equal to zero.
$z-3=0$ and $z+7=0$ Drop the parenthesis.
$z=3$ and $z=-7$ Solve both mini-equations.
