Methemetikcs but anyways yea I don't understand this I'm any way shape or form.​

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

If t17 = 3 (t5) in an arithmetic progression, find t1 in terms of d.

Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city. studies on every subject in the population divide a population in groups and obtain a sample studies with a limited amount of time demonstrate existing traits in a population studies with the nth person selected