Final answer:
The expression for the total number of miles Chang drove in the two weeks is 158 + x, where x represents the number of miles he drove this week.
Step-by-step explanation:
To find the expression for the total number of miles Chang drove in the two weeks, we need to add the number of miles he drove last week to the number of miles he drove this week. Last week he drove 158 miles, and this week he drove an unknown number of miles.
Let's say he drove x miles this week. The expression for the total number of miles he drove in the two weeks is then 158 + x.