Answer:
Trend wants to buy a new bicycle which costs 320$.
He has 35$ saved and earns 15$ each week.
After a number of weeks (a), the amount money he has: A = 35 + 15 x a
If Trend has enough money to buy that bicycle, we have the equation:
35 + 15 x a = 320
=> 15 x a = 320 - 35
=> 15 x a = 285
=> After 19 weeks, Trent will have had enough money to buy that bicycle
Hope this helps!
:)