When you factor an expression why does when you get the same answer factor out.

What is the value of x when x + 7 = 21?

Leslie started last week with $1200 in her checking account. during the week, she wrote the checks below.

Elizabeth claims that the fourth root of 2 can be expressed as 2^m since (2^m)^n = 2. find the values of m and n for the case where elizabeth's claim is true.