Question

Thomas wants to rent a lawn mower. He has to pay a fixed base cost plus a daily rate for renting the lawn mower. The table shows the amount of money, y, in dollars, that Thomas has to pay for renting the lawn mower for x days:

Lawn Mower Rental

Number of days
(x) Rent (dollars)
(y)
0 12
1 21
2 30
3 39
4 48
Which equation best shows the relationship between x and y? (1 point)

a
y = x + 21

b
y = 9x + 21

c
y = 9x + 12

d
y = x + 12

Answer 1

notice how the rent is increasing by 9 per day. (day 0: $12. day 1: $21. 21 - 12 = 9. this pattern continues for the rest of the table, with the rent increasing by 9 each day). this is the rate of change, or slope, for the function.

so for y = mx + b, our m is 9, which gives us y = 9x + b. for the b-value, what's the value of y when x = 0? (a.k.a the y-intercept?) once you have this b-value, plug it into the equation y = 9x + b to complete the equation.