Polar Coordinates and Complex Numbers · Medium problem

$\ 4\left(\cos240^\circ+i\sin240^\circ\right)$

$\ 5\left(\cos240^\circ+i\sin240^\circ\right)$

$-\ 4\left(\cos240^\circ+i\sin240^\circ\right)$

$\ 8\left(\cos240^\circ+i\sin240^\circ\right)$