I need help please lol

Which formula gives the area of a triangle? a=1/2(b+h)

Empty box + box + empty box fill in the box is equal to 30 how

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.