Question

Find the partial derivative zx of the function z(x,y). z=6x^2y+4x^5y

Answer 1

Partial derivative with respect to x?
Treat 'y' as a constant. Then, use the regular power rule on the x terms.

Answer 2

And do what with the y terms? What does treating them like a constant mean?

Answer 3

You leave them alone, as if they were a coefficient.
For example, the partial derivative of the first term is 6y*(2x). I used the power rule on the x term.