Thank you in advanced for your help. This is "urgent" since i am need to leave soon <.<...

I did not catch on right away for this topic. If you can help I'd appreciate it.

If y=x^3 +2x, and dx/dt=5, find dy/dt when x=2

and

If z^2=X^2+y^2, dx/dt=2, and dy/dt=3, find dz/dt when x=5 and y=12.