Multiply all common factors of 9x^6, 15x^4,and 12x^2 to find the gcf.

First find common factor for parameters. I mean to find common factor number 9,15,12
first, write the divisors:
Divisors of 9:  1,3,9
divisors of 12:  1,2,3,4,6,12
divisors of 15: 1,2,3,5,15
so see, that GCF of 9,12,15 is 3.

Now, count GCF of x^2, x^4, x^6
GCF 2,4,6  is 2,  so the result is x^2 
and know finally GCF these terms is