I need help! what is it?

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.

Use the data on the dot plot to answer the question.how many people read for more than three hours last week? i'm on a unit test review

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?