[(-m)^2]^8÷(-m*m^3)÷(-m^2)^3
=(m^2)^8÷(-m^4)÷[-m^(2*3)]
=m^(2*8)÷(-m^4)÷[-m^(2*3)]
=m^16÷m^4÷m^6
=m^(16+4+6)
=m^26