For the first one your equation is h(d)=3/7d+5
If d represents the number of days and the question is wanting to know the height after 1 week (7 days) then you would get this equation once 7 is in the place of d
h(d)=3/7(7)+5
When solved you answer is 8 inch.
For the second one your equation is f(x)=75x+250
If x represents the number of weeks and the question is asking how much money Sam will have after 12 weeks then you will get this equation once putting in 12
f(x)=75(12)+250
Once solved you will get the answer $1150
Hope this helps! :)