1.4.1 Punca Persamaan Kuadratik (Contoh Soalan)


Soalan 1:
Selesaikan persamaan kuadratik, 2 x 2 5 3 = 3 x

Penyelesaian:
2 x 2 5 3 = 3 x
2x2– 5 = 9x
2x2– 9x – 5 = 0
(x – 5) (2x + 1) = 0
x – 5 = 0   atau   2x + 1 = 0
x = 5,  x = –½


Soalan 2:
Selesaikan persamaan kuadratik, 4x2 – 12 = –13x.

Penyelesaian:
4x2– 12 = –13x
4x2+ 13x – 12 = 0
(4x – 3) (x + 4) = 0
4x – 3 = 0   atau   x + 4 = 0
= ¾, x= – 4


Soalan 3:
Selesaikan persamaan kuadratik, 5x2 = 3(x + 2) – 4.

Penyelesaian:
5x2= 3(x + 2) – 4
5x2= 3x + 6 – 4
5x2 – 3x – 2 = 0
(x – 1) (5x + 2) = 0
x – 1 = 0   atau   5x + 2 = 0
= 1, x = 2 5   


Soalan 4:
Selesaikan persamaan kuadratik, 3 x ( x 3 ) 4 = x + 3.

Penyelesaian:
3 x ( x 3 ) 4 = x + 3
3x2– 9x = –4x + 12
3x2 – 5x – 12 = 0
(x – 3) (3x + 4) = 0
x – 3 = 0   atau   3x + 4 = 0
= 3, x = 4 3


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