1) (-1/2m^3)(16m^2)= -1/2*16*m^(3+2)= -8m^5

2) (3/4*х^2*у^3*z)(2/3*x^3*y^2*z^2)=3/4*2/3*x^(2+3)*y^(3+2)*z^(1+2)=1/2*x^5*y^5*z^3

3) (-3/5*a^2*x*y^3)(2/3*a*x^2*y)= -3/5*2/3*a^(2+1)*x^(1+2)*y^(3+1)= -2/5*a^3*x^3*y^4

4) 10 1/3 = 31/10; 1 5/31 = 36/31

(31/10*a*b^2*c^4)(36/31*a^7*b*c^2)= 31/10*36/31*a^(1+7)*b^(2+1)*c^(4+2)= 36/10*a^8*b^3*c^6 = 3,6*a^8*b^3*c^6