Personally if I would of put it in a fraction it be 2/10
We first notice that the sequence of numbers:
12, 21, 30, 39, 48 increases by 9 ($ per day).
We see that these values, related to the days 0, 1, 2, 3, 4 can be written as follows:
12=0*9+12
21=1*9+12
30=2*9+12
39=3*9+12
48=4*9+12
Thus, the price to pay for renting a lawn mower x days is y=9x+12.
Answer: y=9x+12
