An exponent is shorthand for repeated multiplication.  for example, 
n4
=n·n·n·n.   in an exponential expression like ba, b is called the base and a is called the exponent.
expand each of the expressions below. for example, to expand
x3, you would write: x·x·x.

1. y7



2. 5(2m)3



3. (x3)2



4. 4x5y2