Answer :
Part a) [tex] (\frac{4}{7} )^{3}[/tex]
[tex] (\frac{4}{7} )^{3} =\frac{4^{3}}{7^{3}}= \frac{64}{343}[/tex]
therefore
the answer part a) is equal to
[tex] \frac{64}{343} [/tex]
Part b) [tex] \frac{6xyz}{2xz}[/tex]
[tex] \frac{6xyz}{2xz}= \frac{(2xz)(3y)}{2xz} = 3y [/tex]
therefore
the answer Part b) is equal to
[tex] 3y [/tex]