What is the greatest common factor in the expression 6xy3 - 9x2y3 + 15y2z?
Gee whiz. That's visually a bit daunting, but we are doing the exact same thing; we need to take it piece by piece. The number part will be the largest constant that divides 6, 9, and 15, which is 3. The variable x occurs once in the first term, twice in the second, and not at all in the third, and we don't get to use any copies of x. The variable y occurs three times in the first term, three times in the second term, and twice in the third term, and we get two copies of y. The variable z does not occur in the first two terms, and we don't get any copies of z. We can conclude that the greatest common factor for this expression is 3y2. It is a shame, really...z hardly ever gets any time in the spotlight, and here he is getting dissed again. Chin up, z. Your time will come.