2.5.1 SPM Praktis (Soalan Panjang)


SPM Praktis (Soalan Panjang)
 
Soalan 1:
Selesaikan persamaan kuadratik, (y + 3)(y – 4) = 30
 
Penyelesaian:
(y + 3)(y – 4) = 30
y2– 4y + 3y – 12 = 30
y2y – 12 – 30 = 0
y2y – 42 = 0
(y + 6)(y – 7) = 0
+ 6 = 0, y = –6
– 7 = 0
y = 7


Soalan 2:
Selesaikan persamaan kuadratik, 5x2 = 3( x – 2) + 8
 
Penyelesaian:
5x2= 3( x – 2) + 8
5x2= 3x – 6 + 8
5x2– 3x – 2 = 0
(5x + 2)(x – 1) = 0
5x + 2 = 0, x = 2 5
Atau
– 1 = 0
= 1


Soalan 3:
Selesaikan persamaan kuadratik, 2 p 2 15 p = 7
 
Penyelesaian:
2 p 2 15 p = 7  
2p2– 15 = 7p
2p2–7p – 15 = 0
(2p + 3)(p – 5) = 0
2p + 3 = 0, p = 3 2  
– 5 = 0
= 5


Soalan 4:
Selesaikan persamaan kuadratik, y ( y 9 2 ) = 5 2
 
Penyelesaian:
y ( y 9 2 ) = 5 2 y 2 9 y 2 = 5 2
(×2), 2y2– 9y = 5
2y2– 9y – 5 = 0
(2y + 1)(y – 5) = 0
2y + 1 = 0, y = ½
Atau
– 5 = 0
= 5


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