When you end up with prime numbers for example
If you factored out 12 you could say 3x4. Now 3 is a prime number so it cant be broken down any more. You can break down 4 into 2x2. 2 is a prime number so cant be broken down any further. When 12 is factored out it is 2x2x3
10 miles=52800 feet (I know for sure)
Assuming that the number cube is 6 sided
6 is one number in a 6 sided cube, so the probability is: 1/6
heads is one side of the coin, with two in all: 1/2
Multiply the two fractions together
1/6 x 1/2 = 1/12
1/12 is your probability
hope this helps
f(x)=X+7 is {2, 10} then the domain must be 2 is answer