ANSWER
[tex] 2{m}^{3} [/tex]
EXPLANATION
The expressions are
[tex]8 {m}^{3} = {2}^{3} \times {m}^{3} [/tex]
and
[tex]6 {m}^{4} = 2 \times 3 {m}^{4} [/tex]
The greatest common factor is the product the least powers of the common factors.
[tex] = 2 {m}^{3} [/tex]
