pembahasan :

grafik fungsi kuadrat melalui titik(1,0),(3,0),(0,3)

y = ax² + bx + c

melalui (1,0)

0 = a(1)² + b(1) + c

a + b + c = 0

melalui(3,0)

0 = a(3)² + b(3) + c

9a + 3b + c = 0

melalui(0,3)

3 = a(0)² + b(0) + c

c = 3

a + b + c = 0

a + b + 3 = 0

a = -b - 3

9a + 3b + c = 0

9(-b - 3) + 3b + 3 = 0

-9b - 27 + 3b + 3 = 0

-6b = 24

b = -4

a = -b -3

a = -(-4) - 3 = 1

a = 1, b = -4, c = 3

y = ax² + bx + c

y = x² - 4x + 3

titik puncak x = -b/(2a)

x = - -4/(2(1))

x = 2

y = x² -4x + 3

y = 2²- 4(2) + 3

y = -1

titik puncak(2, -1)