A store's rewards program 5 points for joining and 2 points for every item purchased. Select all of the representations that determine the number of reward points earned.

D. y = 0.42x + 55

Step-by-step explanation:

Let the equation for the cost of the truck be represented by y = mx + b,

where y = cost of truck per mile, x = number of miles, m = charge of the truck per mile and b = rental fee.

We are given that,

Cost for Bob's truck ( y ) = $112.96 for x = 138 miles, and

Cost for Carl's truck ( y ) = $142.78 for x = 209 miles.

This gives us the equations,

142.78 = 209m + b

112.96 = 138m + b

Subtracting these equations, we get,

29.82 = 71m

i.e. m = 0.42

Substituting the value of ' m ' in first equation, we get,

142.78 = 209 × 0.42 + b

i.e. 142.78 = 87.78 + b

i.e. b = 55.

Hence, the equation for the cost of the truck is y = 0.42x + 55