Jawabanmu

2014-06-23T12:45:18+07:00
Titik potong terhadap sumbu X maka y = 0
x² - 3x - 4 = 0
<> (x + 1)(x - 4) = 0
<> x = -1 atau x = 4
Luas
= -[-1, 4] Integral (x² - 3x - 4) dx
= -[-1, 4] (x³/3 - 3x²/2 - 4x)
= -[(64 - (-1)) / 3 - (48 - 3)/2 - 4(4 - (-1))]
= -[65/3 - 45/2 - 20]
= -[21 2/3 - 22 1/2 - 20]
= 42 1/2 - 21 2/3
= 20 5/6 satuan luas

atau dengan rumus:
L = D√D / 6a² = 25√25 / 6 = 125/6 = 20 5/6 satuan luas