algebra
posted by Luke on .
I know its true but why?
When you multiply a whole number by a whole number the result is a larger number. When you multiply fractions the result is a smaller number.

Think of it as multiplying the fraction by a whole number. One third three times is 1. The order in which you look at multiplication does not matter, the results are the same. 3x(1/3)=1 and (1/3)x3=1

It is because MOST fractions are smaller than 1. So when you multiply fractions together, they get smaller. On the other hand, ALL integers (except 0) are greater than or equal to 1 (in absolute value), so the product tends to be bigger.
Examples that support what you observe:
2*2=4, 3*2=6,
(1/2)*4=2, (1/2)*(1/4)=1/8
Examples that contest what you observe:
2*0 = 0, 3*1=3 (not bigger)
(4/3)*6=8, (8/3)*(9/4)=6
Hope that answers your question. 
If RS=8y+T,ST=4y+8, and RT=15y9, find the value of y