I need help on this, please !!

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Which pair of numbers is relatively prime? a. 105 and 128 b. 130 and 273 c. 205 and 350 d. 273 and 333

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