If you have a trapezoid top is 10, the bottom is 16 and x is the height. what would be the equation: a) x = 13 over A b) x= A over 13 c) x = A +13 or d) x=A-13

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?