Help me pls i need htis

Which one ? is the answer and how to find this answer

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

Which shows one way to determine the facts of x3+4x2+5x+20 by grouping