what is d/dx of f(x)=[(5)/(x^4/5)]+[(6)/(x^6/7)] ? ???? please help, thank u :)?

Answer 1

Just use the power rule
You have x^ -(4/5) and x^(-6/7) in disguise.
The constants go along for the ride.

Answer 2

f(x)=[25 / x^4] + [42 /x^6]
note: 5/[x^4/5] = 25 / x^4
f(x)=25x^(-4) + 42 x^(-6)
f'(x)= 25 (-4)x^(-5) + 42 (-6)x^(-7)
=-100 / x^5 - 252 / x^7