Question

The parabolic equation that passes trough (-1,0),(3,0),(1,8) is

Answer 1

Y = a(x - x1)(x - x2)
melalui titik (-1,0) dan (3,0) artinya :
y = a(x + 1)(x - 3)

melalui titik (1 , 8)) maka berlaku
8 = a(1 + 1)(1 - 3)
8 = - 4a
a = -2

so, persamaan parabolanya adalah :
y = f(x) = -2(x + 1)(x - 3)
f(x) = -2(x^2 - 2x - 3)
f(x) = -2x^2 + 4x + 6