Tony rented a truck for one day. There was a base fee of $15.00, and there was an additional charge of 10 cents for each mile driven. The total cost, C (in
dollars), for driving x miles is given by the following function
C(x) = 15.00 +0.10x
What is the total rental cost if Tony drove 40 miles?

$20 for 40 miles (including the base fee)

Step-by-step explanation:

C(x) = 15.00 + 0.10m

C(x) = 15.00 + 0.10(40)   | Included the 40 miles

C(x) = 20.00

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this