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To find the area enclosed by the curves $$xy + 4y = 16$$ and $$x + y = 6$$, first rewrite the equations in terms of $$y$$.
The first curve: $$xy + 4y = 16$$ can be factored as $$y(x + 4) = 16$$, so $$y = \frac{16}{x+4}$$ for $$x \neq -4$$.
The second curve: $$x + y = 6$$ can be written as $$y = 6 - x$$.
Next, find the points of intersection by setting the $$y$$-values equal:
$$\frac{16}{x+4} = 6 - x$$
Multiply both sides by $$x+4$$ (assuming $$x \neq -4$$):
$$16 = (6 - x)(x + 4)$$
Expand the right side:
$$16 = 6x + 24 - x^2 - 4x$$
$$16 = -x^2 + 2x + 24$$
Bring all terms to one side:
$$x^2 - 2x - 8 = 0$$
Factor the quadratic:
$$(x - 4)(x + 2) = 0$$
So, $$x = 4$$ or $$x = -2$$.
Find the corresponding $$y$$-values using $$y = 6 - x$$:
When $$x = 4$$, $$y = 6 - 4 = 2$$, so point $$(4, 2)$$.
When $$x = -2$$, $$y = 6 - (-2) = 8$$, so point $$(-2, 8)$$.
The enclosed region is between $$x = -2$$ and $$x = 4$$. To determine which curve is above, evaluate at a test point, say $$x = 0$$:
For the hyperbola: $$y = \frac{16}{0+4} = 4$$.
For the line: $$y = 6 - 0 = 6$$.
Since $$6 > 4$$, the line $$y = 6 - x$$ is above the hyperbola $$y = \frac{16}{x+4}$$ in the interval $$[-2, 4]$$.
The area enclosed is given by the integral:
$$\text{Area} = \int_{-2}^{4} \left[ (6 - x) - \frac{16}{x+4} \right] dx$$
Split the integral into two parts:
$$\text{Area} = \int_{-2}^{4} (6 - x) dx - \int_{-2}^{4} \frac{16}{x+4} dx$$
Compute the first integral:
Antiderivative of $$6 - x$$ is $$6x - \frac{x^2}{2}$$.
Evaluate from $$-2$$ to $$4$$:
At $$x = 4$$: $$6(4) - \frac{(4)^2}{2} = 24 - 8 = 16$$.
At $$x = -2$$: $$6(-2) - \frac{(-2)^2}{2} = -12 - 2 = -14$$.
So, $$\int_{-2}^{4} (6 - x) dx = 16 - (-14) = 30$$.
Now compute the second integral:
$$\int_{-2}^{4} \frac{16}{x+4} dx = 16 \int_{-2}^{4} \frac{1}{x+4} dx$$
Antiderivative of $$\frac{1}{x+4}$$ is $$\ln|x+4|$$.
Evaluate from $$-2$$ to $$4$$:
At $$x = 4$$: $$\ln|4+4| = \ln 8$$.
At $$x = -2$$: $$\ln|-2+4| = \ln 2$$.
So, $$\int_{-2}^{4} \frac{1}{x+4} dx = \ln 8 - \ln 2 = \ln \left( \frac{8}{2} \right) = \ln 4$$.
Thus, $$16 \int_{-2}^{4} \frac{1}{x+4} dx = 16 \ln 4$$.
Since $$\ln 4 = \ln (2^2) = 2 \ln 2$$, this becomes $$16 \times 2 \ln 2 = 32 \ln 2$$.
Therefore, the area is:
$$\text{Area} = 30 - 32 \ln 2$$
Since $$\log_e 2 = \ln 2$$, the area is $$30 - 32 \log_e 2$$.
Comparing with the options:
A. $$28 - 30\log_e 2$$
B. $$30 - 28\log_e 2$$
C. $$30 - 32\log_e 2$$
D. $$32 - 30\log_e 2$$
The expression matches option C.
The correct answer is C.
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