**Soalan 22 (3 markah):**

Rajah menunjukkan graf bagi fungsi

*f*:

*x*→ |1 – 2

*x*| untuk domain –2 ≤

*x*≤ 4.

**Rajah**

Nyatakan

**(a)**objek bagi 7,

**(b)**imej bagi 3,

**(c)**domain bagi 0 ≤

*f*(

*x*) ≤ 5.

*Penyelesaian*:**(a)**

Objek bagi 7 ialah 4.

**(b)**

*f*(

*x*) = |1 – 2

*x*|

*f*(3) = |1 – 2(3)|

= |1 – 6|

= |–5|

= 5

Imej bagi 3 ialah 5.

**(c)**

|1 – 2

*x*| = 5

1 – 2

*x*= ±5

Diberi apabila

*f*(

*x*) = 5,

*x*= –2.

Apabila

*f*(

*x*) = –5

1 – 2

*x*= –5

2

*x*= 6

*x*= 3

Domain: –2 ≤

*x*≤ 3.

**Soalan 23 (4 markah):**

Diberi fungsi

*g*:

*x*→ 2

*x*– 8, cari

$\begin{array}{l}\left(\text{a}\right)\text{}{g}^{-1}\left(x\right),\\ \left(\text{b}\right)\text{nilai}p\text{dengankeadaan}{g}^{2}\left(\frac{3p}{2}\right)=30.\end{array}$

*Penyelesaian*:**(a)**

$\begin{array}{l}\text{Katakan}y=g\left(x\right)\\ \text{}=2x-8\\ 2x-8=y\\ \text{}2x=y+8\\ \text{}x=\frac{y+8}{2}\\ \text{Maka,}{g}^{-1}\left(x\right)=\frac{x+8}{2}\end{array}$

**(b)**

$\begin{array}{l}g\left(x\right)=2x-8\\ {g}^{2}\left(x\right)=g\left[g\left(x\right)\right]\\ \text{}=g\left(2x-8\right)\\ \text{}=2\left(2x-8\right)-8\\ \text{}=4x-16-8\\ \text{}=4x-24\\ {g}^{2}\left(\frac{3p}{2}\right)=30\\ 4\left(\frac{3p}{2}\right)-24=30\\ 6p=54\\ p=9\end{array}$