y' = ((x^4+6)' * (3x+5) - (x^4+6) * (3x+5)')/(3x+5)^2 = (4x^3 * (3x+5) - (x^4+6) * 3)/(3x+5)^2 =
= (12x^4 + 20x^3 - 3x^4 - 18)/(3x+5)^2 = (9x^4 + 20x^3 - 18)/(3x+5)^2
y' = ((x^4+6)' * (3x+5) - (x^4+6) * (3x+5)')/(3x+5)^2 = (4x^3 * (3x+5) - (x^4+6) * 3)/(3x+5)^2 =
= (12x^4 + 20x^3 - 3x^4 - 18)/(3x+5)^2 = (9x^4 + 20x^3 - 18)/(3x+5)^2