tlong dbntu kk.. please..

Xp= 1/2 (4+1) = 5/2
-b/a = 5
b = -5a
c/a = 4
c = 4a
-2 = a.4 + (-5a).2 + 4a
-2 = 4a - 10a + 4a
-2 = -2a
a = 1
y = a(x-x1)(x-x2)
y= (x-4)(x-1)
[tex]y = {x}^{2} - 5x + 4[/tex]