#9
#a
[tex]\\ \sf\longmapsto (y+2z)^3[/tex]
[tex]\\ \sf\longmapsto y^3+2z^3+3y^2(2z)+3y(2z)^2[/tex]
[tex]\\ \sf\longmapsto y^3+8z^3+6y^2z+12yz^2[/tex]
#b
Refer to attachment
#10