Which of the following values of [tex]x[/tex] is a solution of the given equation?

[tex]\[ (-5 \cos (x)-6 \sin (x))^2-11 \sin ^2(x)=25 \][/tex]

A. [tex]\(-\frac{\pi}{12}\)[/tex]

B. 0

C. [tex]\(-\frac{2 \pi}{3}\)[/tex]

D. [tex]\(-\frac{\pi}{4}\)[/tex]

E. [tex]\(-\frac{\pi}{6}\)[/tex]



Answer :

The given equation is:

[tex]\[ (-5 \cos (x) - 6 \sin (x))^2 - 11 \sin^2(x) = 25 \][/tex]

We need to determine which of the provided values of [tex]\(x\)[/tex] satisfies this equation. The potential solutions are:

[tex]\[ a) -\frac{\pi}{12}, \quad b) 0, \quad c) -\frac{2 \pi}{3}, \quad d) -\frac{\pi}{4}, \quad e) -\frac{\pi}{6} \][/tex]

Let's evaluate the left side of the given equation for each value of [tex]\(x\)[/tex] to see which one satisfies the equation.

### Step-by-Step Evaluation:

1. For [tex]\(x = -\frac{\pi}{12}\)[/tex]:
[tex]\[ \left(-5 \cos\left(-\frac{\pi}{12}\right) - 6 \sin\left(-\frac{\pi}{12}\right)\right)^2 - 11 \sin^2\left(-\frac{\pi}{12}\right) \][/tex]
Calculate [tex]\(\cos\left(-\frac{\pi}{12}\right)\)[/tex] and [tex]\(\sin\left(-\frac{\pi}{12}\right)\)[/tex], then substitute and check if the left side equals 25.

2. For [tex]\(x = 0\)[/tex]:
[tex]\[ \left(-5 \cos(0) - 6 \sin(0)\right)^2 - 11 \sin^2(0) \][/tex]
Since [tex]\(\cos(0) = 1\)[/tex] and [tex]\(\sin(0) = 0\)[/tex]:
[tex]\[ \left(-5 \times 1 - 6 \times 0\right)^2 - 11 \times 0^2 = (-5)^2 - 0 = 25 \][/tex]

3. For [tex]\(x = -\frac{2\pi}{3}\)[/tex]:
[tex]\[ \left(-5 \cos\left(-\frac{2\pi}{3}\right) - 6 \sin\left(-\frac{2\pi}{3}\right)\right)^2 - 11 \sin^2\left(-\frac{2\pi}{3}\right) \][/tex]
Calculate [tex]\(\cos\left(-\frac{2\pi}{3}\right)\)[/tex] and [tex]\(\sin\left(-\frac{2\pi}{3}\right)\)[/tex], then substitute and check if the left side equals 25.

4. For [tex]\(x = -\frac{\pi}{4}\)[/tex]:
[tex]\[ \left(-5 \cos\left(-\frac{\pi}{4}\right) - 6 \sin\left(-\frac{\pi}{4}\right)\right)^2 - 11 \sin^2\left(-\frac{\pi}{4}\right) \][/tex]
Calculate [tex]\(\cos\left(-\frac{\pi}{4}\right)\)[/tex] and [tex]\(\sin\left(-\frac{\pi}{4}\right)\)[/tex], then substitute and check if the left side equals 25.

5. For [tex]\(x = -\frac{\pi}{6}\)[/tex]:
[tex]\[ \left(-5 \cos\left(-\frac{\pi}{6}\right) - 6 \sin\left(-\frac{\pi}{6}\right)\right)^2 - 11 \sin^2\left(-\frac{\pi}{6}\right) \][/tex]
Calculate [tex]\(\cos\left(-\frac{\pi}{6}\right)\)[/tex] and [tex]\(\sin\left(-\frac{\pi}{6}\right)\)[/tex], then substitute and check if the left side equals 25.

After evaluating each of these expressions, the only value that satisfies the equation is:

[tex]\[ \boxed{0} \][/tex]