Answer:
x=6
Explanation:
Equation setup for problem: Total = Initial + (daily) x
Plug in values ->
161 = 35 + (21) x
Subtract 35 from both sides ->
126 = 21 x
Divide both sides by 21 ->
6 = x
So x is the number of days he had the car, so he had it for 6 days.