Find all extrema for the function

y=x^5-2x^3+3 on the interval [-10...10]

dy/dx = 5 x^4 - 6 x^2

slope = dy/dx = 0 at max or min

x^2 (5 x^2 - 6 ) = 0
x = 0 or x = -6/5 or x = +6/5