How can i tell if f(x)=400 in f(x)=4x-9 or if t(n)=400 in t(n)=4n-9?

What is the value of x in the figure below? if necessary, round your answer to the nearest tenth of a unit. 12 d 4 b оа. 3.1 ов. 6.9 ос. 4 od. 12

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.

What is the slope of the line that contains the points (-2,1) and (0,-3)