Simplify

[tex]\[
\frac{3-4i}{9+4i}
\][/tex]

A. [tex]\(\frac{11}{97}+\frac{48}{97}i\)[/tex]

B. [tex]\(\frac{11}{97}-\frac{48}{97}i\)[/tex]

C. [tex]\(-\frac{11}{97}+\frac{48}{97}i\)[/tex]

D. [tex]\(-\frac{11}{97}-\frac{48}{97}i\)[/tex]

Please select the best answer from the choices provided:

A

B

C

D



Answer :

To simplify the complex fraction [tex]\(\frac{3-4i}{9+4i}\)[/tex], we need to multiply both the numerator and the denominator by the conjugate of the denominator. The conjugate of [tex]\(9+4i\)[/tex] is [tex]\(9-4i\)[/tex].

Here's the detailed step-by-step solution:

1. Identify the complex fraction to be simplified:
[tex]\[ \frac{3-4i}{9+4i} \][/tex]

2. Multiply the numerator and the denominator by the conjugate of the denominator:
[tex]\[ \frac{(3-4i)(9-4i)}{(9+4i)(9-4i)} \][/tex]

3. Use the formula for multiplying complex numbers:
[tex]\[ (a+bi)(c+di) = (ac-bd) + (ad+bc)i \][/tex]

4. For the numerator [tex]\((3-4i)(9-4i)\)[/tex]:
[tex]\[ 3 \cdot 9 + 3 \cdot (-4i) - 4i \cdot 9 - 4i \cdot (-4i) \][/tex]
[tex]\[ = 27 - 12i - 36i + 16i^2 \][/tex]
Since [tex]\( i^2 = -1 \)[/tex], we have:
[tex]\[ = 27 - 12i - 36i + 16(-1) \][/tex]
[tex]\[ = 27 - 12i - 36i - 16 \][/tex]
[tex]\[ = 11 - 48i \][/tex]

5. For the denominator [tex]\((9+4i)(9-4i)\)[/tex]:
[tex]\[ 9 \cdot 9 + 9 \cdot (-4i) + 4i \cdot 9 - 4i \cdot 4i \][/tex]
[tex]\[ = 81 - 36i + 36i - 16i^2 \][/tex]
Since [tex]\( i^2 = -1 \)[/tex], we have:
[tex]\[ = 81 - 16(-1) \][/tex]
[tex]\[ = 81 + 16 \][/tex]
[tex]\[ = 97 \][/tex]

6. Combine the results:
[tex]\[ \frac{11 - 48i}{97} \][/tex]

7. Separate the real and imaginary parts:
[tex]\[ \frac{11}{97} - \frac{48}{97}i \][/tex]

Thus, the simplified form of the given complex fraction is:
[tex]\[ \frac{11}{97} - \frac{48}{97}i \][/tex]

From the provided options, the correct answer is:

c. [tex]\(\frac{11}{97} - \frac{48}{97} i \)[/tex]