A critical point is just where a graph's slope is = to 0, so you can take the derivative of that function and set it equal to 0.
Using the chain rule: f'(x) = 5(x-10)^4 0 = 5(x-10)^4
divide by 5 on both sides and take the 4th root of both sides.
0 = x - 10
add ten on both sides, and x = 10. Now, plug the x-value back into the original (you want to find the y-value on the original function ,not the derivative).
