consider
[tex]3g^2+2g^2-4g[/tex]note that the letter g is common to all the numbers in the equation, so we take the lowest power of g and make a common factor, that is:
[tex]3g^2+2g^2-4g=g(3g+2g-4)^{}\text{ = g(5g - 4)}[/tex]so the correct answer is
g(5g - 4)