Gee whiz. That's visually a bit daunting, but we just 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, so 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, so we get two copies of *y*. The variable *z* doesn't occur in the first two terms, so we don't get any copies of *z*. We can conclude that the greatest common factor for this expression is 3*y*^{2}. It's 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. | |