What is the derivative of 1/√(7-4x)

I think i have the right answer, I just want clarification with steps also.

Let y = (7-4x)^-1/2
Differentiate
dy/dx =(-1/2){(7-4x)^(-3/2)}(-4)
= 2/(7-4x)^3/2 ................Ans

y=(7-4x)^(-1/2)

y'=(-1/2)*(7-4x)^(-3/2)*(-4)