3m•2n•0,4mn^3=2m^2•n^3
71/3 b^3 c^2•9/11 a^4 b^5=6a^4 b^8 c^2
-5x^4 y^2 z^8•(-0,8x^6 y^8 z^2)=4x^10 y^10 z^10=4(〖xyz)〗^10
-53/7 abc•3,5a^12 b^10 c=19a^13 b^11 c^2
3m•2n•0,4mn^3=2m^2•n^3
71/3 b^3 c^2•9/11 a^4 b^5=6a^4 b^8 c^2
-5x^4 y^2 z^8•(-0,8x^6 y^8 z^2)=4x^10 y^10 z^10=4(〖xyz)〗^10
-53/7 abc•3,5a^12 b^10 c=19a^13 b^11 c^2