I think you need to explain more for one to answer it.
Please give more details and I'll try to help (if this is meant to be a question)
Oceans one ocean at a time
Step 1. Substitute y for f(x)
Step 2. Switch x and y.
Step 3. Solve for y.
Step 4. Substitute f(x) for y.
the answer is “s = 10w + 35” since he already has 35 but needs to find out how many weeks he washed the dishes :))