turunan pertama dari y= (x+2)(x+1)/(x+3) adalah

y = (x² + 3x + 2)/(x + 3)
u = x² + 3x + 2 → u'= 2x + 3
v = x + 3 → v' = 1
y' = (u'v - v'u)/v²
= ((2x + 3)(x + 3) - 1(x² + 3x + 2))/(x + 3)²
= (2x² + 9x + 9 - x² - 3x - 2)/(x + 3)²
= (x² + 6x + 7)/(x + 3)²

y = (x + 2)(x + 1) / (x + 3)
   = (x² + 3x + 2) / (x + 3)

y' = [(2x + 3)(x + 3) - (x² + 3x + 2)(1)] / (x + 3)²
    = (2x² + 6x + 3x + 9 - x² - 3x - 2) / (x + 3)²
    = (x² + 6x + 7) / (x + 3)²