Can someone please explain the steps on how to do this please ?

Find the value of x that will make l ll m

Proportions in triangles solve for x

Ben frank is an electrician who installs lighting fixtures. he charges (in dollars) his clients 15h+40f15h+40f where hh is the number of hours worked and ff is the number of fixtures installed. how much does ben frank charge when he works 77 hours and installs 99 fixtures?