1. y' = 8/3 * x^3 + 3/2 * x^2 + 2x
2. y' = (6x^5 - 9x - 4x^4 + 6)' = 30x^4 - 9 - 16x^3
3. y' = ((3x-8)'(x+8) - (3x-8)(x+8)')/(x+8)^2 = (3(x+8)-(3x-8))/(x+8)^2 = (3x + 24 -3x + 8)/(x+8)^2 = 32/(x+8)^2
4. y' = 28(2x^2 - 6x - 3)^6 * (4x - 6)
5. y' = -sinx - 2cosx