Question

Tentukan akar-akar selesaian dari x2 - 9x + 14 =0 Dengan cara melengkapkan kuadrat

Answer 1

X^2 + (-9)x + 14 = 0
x^2 + (-9)x + 14 - 14 = 0 + 14
x^2 + (-9)x = -14
x^2 + (-9)x + (-9/2)^2 = -14 + (-9/2)^2
x^2 + (-9)x + 81/4 = -14 + 81/4
x^2 + (-9)x + 81/4 = 25/4
(x-9/2)^2 = 25/4


1. x - 9/2 = 5/2
2. x - 9/2 = -5/2

x = 7
x = 2