Since a product in maths means the result after multiplying numbers, you need to multiply 2 prime numbers and get 4.
If we look at the prime numbers: 2, 3, 5, 7, 11, etc, we see that the only number we can multiply to get 4 is 2, or, in other words, the only multiplication of prime numbers we can do to get four is 2*2=4.
Well you would subtract 137-74, the number that it equals is your answer (:
6y-8<10
6y<18 add 8 to both sides
y<3 divide both sides by 6
1/2 because he has 16 pieces gives 4/8 which is a half and therefore has a half left
-x+5y=20
5y=x+20
12y=2x+60
6y=x+40
x+20+y=x+40
-x from each side:
20+y=40
-20 from each side:
y=20
-x+5*20=20
-x+100=20
-100 from each side:
-x=-80
x=80
y=20
x=80
Hope this helps :)
