Plz help i suck at math

Jabari is power washing houses for a summer job. for every job, he charges an initial fee plus $30 for each hour of work. his total fee for a 4 -hour job, for instance, is $170 . jabari's total fee,f, for a single job is a function of the number,t, of hours it takes him to complete the job. write the function's formula.

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours

What is the point slope form of a line with slope -5 that contains point (2,-1)