6) y=(x²+9)·(x⁶-10)

y' = 2x(x⁶-10) + (x²+9)6x⁵ = 2x⁷ - 20x + 6x¹¹ + 54x⁵ = 6x¹¹ + 2x⁷ + 54x⁵ - 20x