bantu no 4-5 dg jalan nya

4) f(x) = x^2 - 4x - 12

Memotong sumbu x jika f(x) = y = 0
x^2 - 4x - 12 = 0
(x - 6)(x + 2) = 0
x = 6 atau x = -2
(6,0) dan (-2,0)

Memotong sumbu y jika x = 0
y = f(0) = 0^2 - 4(0) - 12 = -12 => (0, -12)

5) titik puncak = (xp, yp) = (-1, 4) dan melalui (x,y) = (1,0)
y = a(x - xp)^2 + yp
0 = a(1 - (-1))^2 + 4
0 - 4 = a(2)^2
-4 = 4a
a = -1
y = a(x - xp)^2 + yp
y = -1(x + 1)^2 + 4
y = -1(x^2 + 2x + 1) + 4
y = -x^2 - 2x - 1 + 4
y = -x^2 - 2x + 3