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If (x + iy)(2 - 3i) = 4 - i, find the real values of x and y.
Question

If (x + iy)(2 - 3i) = 4 - i, find the real values of x and y.

A.

x=1413,y=513x = \frac{14}{13}, y = \frac{5}{13}

B.

x=513,y=1413x = \frac{5}{13}, y = \frac{14}{13}

C.

x=213,y=1x = \frac{2}{13}, y = 1

D.

x=1113,y=1013x = \frac{11}{13}, y = \frac{10}{13}

Correct option is D

Solution:

1. Expand the expression:
(x+iy)(23i)=2x3xi+2iy3iy2(x + iy)(2 - 3i) = 2x - 3xi + 2iy - 3iy^2
Since i2i^2​ = -1, this simplifies to:
2x - 3xi + 2iy + 3y
Rearrange into real and imaginary parts:
(2x + 3y) + (-3x + 2y)i

2. Equate to the given value 4 – i :
(2x + 3y) + (-3x + 2y)i = 4 - i
Equating real and imaginary parts:
2x+3y=4(1)2x + 3y = 4 \tag{1}
3x+2y=1(2)-3x + 2y = -1 \tag{2}

3. Solve the system of equations:
From equation (1):
x=43y2(3)x = \frac{4 - 3y}{2} \tag{3}
Substitute equation (3) into equation (2):
3(43y2)+2y=1-3\left(\frac{4 - 3y}{2}\right) + 2y = -1
Simplify:
129y2+2y=1-\frac{12 - 9y}{2} + 2y = -1
Multiply through by 2 to eliminate the fraction:
-12 + 9y + 4y = -2
Combine terms:
13y=10=>y=101313y = 10 \quad \Rightarrow \quad y = \frac{10}{13}

4. Substitute y = 1013\frac{10}{13}​ into equation (3):
x=43(1013)2x = \frac{4 - 3\left(\frac{10}{13}\right)}{2}
Simplify:
x=430132=521330132=22132=1113x = \frac{4 - \frac{30}{13}}{2} = \frac{\frac{52}{13} - \frac{30}{13}}{2} = \frac{\frac{22}{13}}{2} = \frac{11}{13}

Final Answer:

The values are:
x=1113,y=1013x = \frac{11}{13}, \quad y = \frac{10}{13}
Correct Option: **(D)**

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