Graph the line that passes through the point (-2,4) and has a slope of -3

Can someone explain the elimination method to me for this problem?

Which of the following is an example of a rational number? a. π b. √ 9 c. √ 8 d. 3.8362319

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