ANSWER
The greatest common factor is
[tex]8[/tex]
EXPLANATION
We want to find the greatest common factor of
[tex]8x \: and \: 40.[/tex]
We use prime factorization to find the greatest common factor of
[tex]8x \: \: and \: \: 40.[/tex]
The prime factorization of 8x is,
[tex]8x = {2}^{3} \times x[/tex]
The prime factorization of 40 is
[tex]40 = {2}^{3} \times 5[/tex]
The greatest common factor of 8x and 40 is
[tex] {2}^{3} = 8[/tex]
