Plity -2 -6.452 - 6+(-3.252).​

An an average person has 6×10 by the power of two as many red blood cells as white blood cells a small sample of the blood has 7×10 by the power of three white blood cells about how many red blood cells are in the sample

Which expression demonstrates the use of the commutative property of addition in the first step of simplifying the expression (-1+i)+(21+5i)+0

Having a hard time understanding this question (see attachment).