Answer:
y(x)=0.8x+2.1
x=12 miles
Step-by-step explanation:
Let x represent the number of miles covered and with a fixed charge of 2.1 irrespective of miles covered then the equation can be written as
y(x)=0.8x+2.1
Substituting y(x) with 11.7 then
11.7=0.8x+2.1
0.8x=11.7-2.1=9.6
X=9.6/0.8=12 miles