Expanding the first term:

0.6m(2m-1)(2m+1)
= 0.6m(4m^2 - 1)
= 2.4m^3 - 0.6m

Expanding the second term:

0.3(6+5m)(6-5m)
= 0.3(36 - 30m + 30m - 25m^2)
= 0.3(36 - 25m^2)
= 10.8 - 7.5m^2

Adding the two terms together:

2.4m^3 - 0.6m + 10.8 - 7.5m^2
= 2.4m^3 - 7.5m^2 - 0.6m + 10.8