Answer
$4.4995-5.3623i$
Work Step by Step
$7$ cis $310^{\circ}=7(\cos 310^{\circ}+i\sin 310^{\circ})$
Using a calculator, we find that $\cos310^{\circ}=0.64279$ and $\sin310^{\circ}=-0.76604$
Substituting these values in the expression and solving:
$7(\cos310^{\circ}+i\sin310^{\circ})=7(0.64279-0.76604i)=4.4995-5.3623i$
