Can somone please help

How do you find principle and simple interest

25 ! the line of best fit is h = 5a + 86. predict the height at age 16.

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.