We need to find the greatest common factor of
[tex]64a^8b^4,56a^5b^8[/tex]We will find the greatest common factor of 64 and 56, first
Since the factors of 64 are
[tex]\begin{gathered} 1\times64 \\ 2\times32 \\ 4\times16 \\ 8\times8 \\ 1,2,4,8,16,32,64 \end{gathered}[/tex]Since the factors of 56 are
[tex]\begin{gathered} 1\times56 \\ 2\times28 \\ 4\times14 \\ 8\times7 \\ 1,2,4,7,8,14,28,56 \end{gathered}[/tex]Then the common factors are 1, 2, 4, 8
The greatest is 8, then
The GCF of 64 and 56 is 8
The greatest common factor of the same variables is the least power
Then the GCF of a^8 and a^5 is a^5
The GCF of b^4 and b^8 is b^4
Then the greatest common factor of the given terms is
[tex]\text{GCF}=8a^5b^4[/tex]