Question

Perform the indicated multiplication below. Reduce terms and simplify. Include all of the necessary steps and calculations in your final answer.
(2 + i)(3 - i)(1 + 2i)(1 - i)(3 + i)

Answer 1

Complex numbers multiplication is commutative.
so 

given 
= (2+i)(1+2i) * (3-i)(3+i) * (1-i)

|(2+i)(1+2i)| has 5 as its absolute value and geometrically thinking its argument is pi/2. so

(2+i)(i+2i) = 5i

and obviously 

(3+i)(3-i) = 10

so the answer is 

50i * (1-i) = 50 + 50i

maybe, I think...