Step-by-step explanation:
Look at both terms separately, and isolate each "part."
i.e. 12x^4y^2 becomes 12, x^4, y^2
So the problem becomes:
12, x^4, y^2 and
30, x^3, y^1
Then, find the GCF of each term,
30 and 12 - 6
x^4 and x^3 - x^3
y^2 and y^1 - y^1
Hope it helps :) and let me know if you want me to elaborate.