7.8335 is a number between 7.833 and 8.834
6 faces, 12 edges, and 8 vertices
The answer is

first you must multiply or use the FOIL method (First, Outer, Inner, Last)
First you multiply the first terms

this gives you 3x^2, then you multiple the outer terms

this gives you -21x, then you multiply the inner terms

that gives you 2x, finally you multiply the last terms

that gives you 14, now you combine like terms

now you put all the terms together and end up with your solution
5 and 3 are two primary numbers for this question
60 mins in an hour
18/60 is the fraction
3/10 is the simplest form (dividing by 6)