1. **State the problem:** We are given two functions:
$$f(x) = \frac{1}{2}x + 5$$
$$g(x) = x^2$$
We need to evaluate:
(i) $g(3) + g(-3)$
(ii) $f^{-1}(6)$ (the inverse of $f$ evaluated at 6)
(iii) $fg(2)$ (which means $f(g(2))$)
2. **Evaluate (i) $g(3) + g(-3)$:**
Since $g(x) = x^2$, we have:
$$g(3) = 3^2 = 9$$
$$g(-3) = (-3)^2 = 9$$
Adding these:
$$g(3) + g(-3) = 9 + 9 = 18$$
3. **Find $f^{-1}(6)$:**
The inverse function $f^{-1}$ satisfies $f(f^{-1}(x)) = x$.
Start with:
$$y = f(x) = \frac{1}{2}x + 5$$
To find $f^{-1}$, solve for $x$ in terms of $y$:
$$y = \frac{1}{2}x + 5$$
Subtract 5 from both sides:
$$y - 5 = \frac{1}{2}x$$
Multiply both sides by 2:
$$2(y - 5) = \cancel{2} \times \frac{1}{2}x = x$$
So,
$$f^{-1}(y) = 2(y - 5)$$
Now evaluate at $y=6$:
$$f^{-1}(6) = 2(6 - 5) = 2(1) = 2$$
4. **Evaluate $fg(2)$:**
This means $f(g(2))$.
First find $g(2)$:
$$g(2) = 2^2 = 4$$
Now find $f(4)$:
$$f(4) = \frac{1}{2} \times 4 + 5 = 2 + 5 = 7$$
**Final answers:**
(i) $18$
(ii) $2$
(iii) $7$
Function Evaluation 987825
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