1) y = x^n
2) y' = nx^n-1 (y' means take the derivative of the function with respect to x, so use the simple power rule!)
Piece of cake! One of the most helpful rules in calculus, because if you didn't have the simple power rule, then you would have to use the general form for a derivative, which takes alot longer than the method above.
y = 3x^(-2)
y = 12x^0
y = 3x^(1/2)
y'= (3/2)x^(-1/2) or 3/2 times 1/squareroot of x