Gerald wants to purchase a tennis racket and some cans of tennis balls. The table below shows the total prices he would pay at a discount store to buy one tennis racket and 1 to 4 cans of tennis balls.

Number of Cans of Tennis Balls	Total Price with Racket
1	$43
2	$46
3	$49
4	$52

 

1. Write an expression that can be used to find the total price for one tennis racket and b cans of tennis balls. Explain your reasoning. 
2. Also ,

3. Gerald purchased one tennis racket and b cans of tennis balls. The total price of his purchase was $70. How many cans of tennis balls did Gerald purchase? Show or explain how you got your answer.