Answered

If [tex]\( f(x) = 6 - 2x \)[/tex], [tex]\( g(x) = \frac{9}{x} \)[/tex], and [tex]\( h(x) = 6 + x^2 \)[/tex], then find:

a) [tex]\( f(-1) \)[/tex]

b) [tex]\( g\left(\frac{1}{3}\right) \)[/tex]

c) [tex]\( h(f(x)) \)[/tex]

d) [tex]\( g(f(x)) \)[/tex]

e) [tex]\( f(g(12)) \)[/tex]

f) [tex]\( h(f(-9)) \)[/tex]



Answer :

Sure, let's tackle each part of the question step-by-step.

### Definitions:
Given the functions:
- [tex]\( f(x) = 6 - 2x \)[/tex]
- [tex]\( g(x) = \frac{9}{x} \)[/tex]
- [tex]\( h(x) = 6 + x^2 \)[/tex]

### a) Evaluate [tex]\( f(-1) \)[/tex]:
To find [tex]\( f(-1) \)[/tex]:
[tex]\[ f(-1) = 6 - 2(-1) = 6 + 2 = 8 \][/tex]

### b) Evaluate [tex]\( g\left(\frac{1}{3}\right) \)[/tex]:
To find [tex]\( g\left(\frac{1}{3}\right) \)[/tex]:
[tex]\[ g\left(\frac{1}{3}\right) = \frac{9}{\frac{1}{3}} = 9 \times 3 = 27 \][/tex]

### c) [tex]\( h(f(x)) \)[/tex]:
To express [tex]\( h(f(x)) \)[/tex], we first find [tex]\( f(x) \)[/tex] and then substitute it into [tex]\( h(x) \)[/tex].
[tex]\[ f(x) = 6 - 2x \][/tex]
Now substitute [tex]\( f(x) \)[/tex] into [tex]\( h(x) \)[/tex]:
[tex]\[ h(f(x)) = h(6 - 2x) = 6 + (6 - 2x)^2 \][/tex]
Simplify the expression inside the square:
[tex]\[ (6 - 2x)^2 = 36 - 24x + 4x^2 \][/tex]
Thus,
[tex]\[ h(6 - 2x) = 6 + 36 - 24x + 4x^2 = 42 - 24x + 4x^2 \][/tex]
So,
[tex]\[ h(f(x)) = 42 - 24x + 4x^2 \][/tex]

### d) [tex]\( gf(x) \)[/tex]:
To express [tex]\( gf(x) \)[/tex], we find [tex]\( f(x) \)[/tex] first and then substitute it into [tex]\( g(x) \)[/tex]:
[tex]\[ f(x) = 6 - 2x \][/tex]
Now substitute [tex]\( f(x) \)[/tex] into [tex]\( g(x) \)[/tex]:
[tex]\[ g(f(x)) = g(6 - 2x) = \frac{9}{6 - 2x} \][/tex]
So,
[tex]\[ g(f(x)) = \frac{9}{6 - 2x} \][/tex]

### e) Evaluate [tex]\( f(g(12)) \)[/tex]:
To find [tex]\( f(g(12)) \)[/tex]:
First, evaluate [tex]\( g(12) \)[/tex]:
[tex]\[ g(12) = \frac{9}{12} = \frac{3}{4} \][/tex]
Now, substitute this value into [tex]\( f(x) \)[/tex]:
[tex]\[ f\left(\frac{3}{4}\right) = 6 - 2 \left(\frac{3}{4}\right) = 6 - \frac{3}{2} = 6 - 1.5 = 4.5 \][/tex]

### f) Evaluate [tex]\( h(f(-9)) \)[/tex]:
To find [tex]\( h(f(-9)) \)[/tex]:
First, evaluate [tex]\( f(-9) \)[/tex]:
[tex]\[ f(-9) = 6 - 2(-9) = 6 + 18 = 24 \][/tex]
Now, substitute this value into [tex]\( h(x) \)[/tex]:
[tex]\[ h(24) = 6 + 24^2 = 6 + 576 = 582 \][/tex]

### Summary of Results:
[tex]\[ \begin{aligned} &\text{a) } f(-1) = 8 \\ &\text{b) } g\left(\frac{1}{3}\right) = 27 \\ &\text{c) } h(f(x)) = 42 - 24x + 4x^2 \\ &\text{d) } g(f(x)) = \frac{9}{6 - 2x} \\ &\text{e) } f(g(12)) = 4.5 \\ &\text{f) } h(f(-9)) = 582 \\ \end{aligned} \][/tex]