Titik2 = (0,30),(3,0),(5,0)
y = ax² + bx + c
(0,30)
30 = a(0) + b(0) + c
c = 30
y = ax² + bx + 30
(3,0)
0 = 3²a + 3b + 30
0 =9a + 3b + 30
0 = 3a + b + 10
3a + b = -10
(5,0)
0 = 5²a + 5b + 30
-30 = 25a + 5b (x1) -30 = 25a + 5b
-10 = 3a + b (x5) -50 = 15a + 5b -
20 = 10a
a = 2
3a + b = -10
3(2) + b = -10
6 + b = -10
b = -16
y = ax² + bx + c
y = 2x² -16x + 30 (D)