# Structure in expressions challenge

Review your skills for using the structure of expressions with some challenge problems.

### Problem

The position, p, of a particle is expressed in terms of time as:
p, equals, left parenthesis, t, minus, a, right parenthesis, left parenthesis, t, minus, b, right parenthesis, left parenthesis, b, minus, t, right parenthesis where
a, is greater than, b
Which value is greater?
Please choose from one of the following options.