Page 25 - Buku Teks Digital Mate KSSM T5

Bab 1 Fungsi dan Persamaan Kuadratik dalam Satu Pemboleh Ubah

Penyelesaian:
1 2
BAB (a) f (x) = x – 4x + 3 f (x)

Nilai a = 1 > 0, bentuk

Nilai c = 3, pintasan-y = 3 3
Apabila f (x) = 0, x – 4x + 3 = 0
2
( x – 3)(x – 1) = 0 x

x = 1 atau x = 3 O 1 3

(b) f (x) = x – 6x + 9
2
f (x)

Nilai a = 1 > 0, bentuk
9
Nilai c = 9, pintasan-y = 9
Apabila f (x) = 0, x – 6x + 9 = 0
2
( x – 3)(x – 3) = 0 x
x = 3 O 3

2
(c) f (x) = –x + 2x + 15
f (x)

Nilai a = –1 < 0, bentuk
15
Nilai c = 15, pintasan-y = 15
Apabila f (x) = 0, –x + 2x + 15 = 0
2
2
x – 2x – 15 = 0
( x – 5)(x + 3) = 0 –3 O 5 x
x = –3 atau x = 5

(d) f (x) = –2x + 18
2
Nilai a = –2 < 0, bentuk f (x)

Nilai b = 0, paksi simetri ialah paksi-y
18
Nilai c = 18, pintasan-y = 18

2
Apabila f (x) = 0, –2x + 18 = 0
2
x – 9 = 0
( x + 3) (x – 3) = 0 x
x = –3, x = 3 –3 O 3

Saiz sebenar

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