HELP??? pls im stuck.

Factor the expression using the gcf. the expression 21m−49n factored using the gcf

Divide. –4.2 ÷ 6 = a –0.7 b 0.7 c –7 d 7 me

Tony is charged $ 50 and additional $0.15 per miles for renting a car. a) represent the cost of renting a car with an equation,and the determine the cost if he drove it70 miles.b) what would be the cost of a car rental if the car was driven 250 miles? show work