Find the derivative for these:
y = 6xe^{−kx So for this I'm getting 6-ke^x }
y =(square root the whole equation)
5 + 2e^{8x}
This one I'm not entirely sure how to do, maybe (a-b)^2?
Your question's pretty unclear, but I'm assuming you want to find dy/dx?
For the first one, you have to use the product rule:
$\displaystyle \frac{dy}{dx} = 6(e^{-kx} + x(e^{-kx})(-k))$, then simplify.
The second one's just a chain rule problem. I don't know what you're referring to when you say $\displaystyle (a-b)^2$...