Fungsi kuadrat yg grafiknya memotong sumbu x di titik (1,0) (4,0) (-1,10)

titik ( 1 ,0 ) —-> x = 1 dan y = 0
x = 1
x – 1 = 0

titik ( 4 , 0 ) —-> x = 4 dan y = 0
x = 4
x – 4 = 0

( x – 1 ) ( x – 4 ) = 0
x² – 4x – x + 4 = 0
x² – 5x + 4 = 0

titik ( -1 , 10 ) —-> x = -1 dan y = 10
masukkan nilainya ke persamaan

y = a ( x² – 5x + 4 )
10 = a ( (-1)² – 5 (-1) + 4 )
10 = a ( 1 + 5 + 4 )
10 = 10 a
a = 10/10
a = 1

masukkan nilai a = 1
y = a ( x² – 5x + 4 )
y = x² – 5x + 4

jawaban nya : y = x² – 5x + 4