X (3 m) 2 = x 20, then m=log3( 10).

[(-y)^2]^5 *[(-y)^3]^2*(-y)^8

=(y^ 10)*(y^6)*(y^8)

=y^24

(-y^2)^5*(-y^3)^2*(-y^8)

=(-y^ 10)*y^6*(-y^8)

=y^24

Because x m * x (2m) = 2,

That is, x (3m) = 2,

So x (9m) = [x (3m)] 3 = 2 3 = 8.