find the derivative of

Question

y = sqrt(9 - 16x)

Use the chain rule. First find the derivative of the sqrt, and multiply that by the derivative of what is contained inside.

Cake.

Use the chain rule. If we have y(x)=sqrt(9-16x) then
y'=d/dx(sqrt(9-16x))*d/dx(9-16x)
The first deriv. is (1/2)(9-16x)^(-1/2), you should be able to finish it.