Christa is saving for a new tablet. It costs $70, including tax. She has already saved $35. How much more does she need to save? ***I know that the answer is $35, but my teacher wants it in algebraic form.

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.