(a) \frac{(5-j 6)-(2+j 8)}{(-3+j 4)(5-j)+(4-j 6)}
(b) \frac{\left(240 \angle 75^{\circ}+160 \angle-30^{\circ}\right)(60-j 80)}{(67+j 84)\left(20 \angle 32^{\circ}\right)}
(c) \left(\frac{10+j 20}{3+j 4}\right)^{2} \sqrt{(10+j 5)(16-j 120)}
(a) \frac{(5-j 6)-(2+j 8)}{(-3+j 4)(5-j)+(4-j 6)}
(b) \frac{\left(240 \angle 75^{\circ}+160 \angle-30^{\circ}\right)(60-j 80)}{(67+j 84)\left(20 \angle 32^{\circ}\right)}
(c) \left(\frac{10+j 20}{3+j 4}\right)^{2} \sqrt{(10+j 5)(16-j 120)}