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Mathematics

Solution of equation 2x+3y\dfrac{2}{x} + \dfrac{3}{y} + 1 = 0 and 3x+5y\dfrac{3}{x} + \dfrac{5}{y} + 2 = 0 is:

  1. -1 and -1

  2. -1 and -2

  3. 1 and -1

  4. none of these

Linear Equations

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Answer

Given, 2x+3y\dfrac{2}{x} + \dfrac{3}{y} + 1 = 0 and 3x+5y\dfrac{3}{x} + \dfrac{5}{y} + 2 = 0

Let 1x\dfrac{1}{x} be u and 1y\dfrac{1}{y} be v.

⇒ 2u + 3v + 1 = 0 ……………….(1)

⇒ 3u + 5v + 2 = 0 ……………….(2)

Multiplying eq. (1) by 3, we get,

⇒ 6u + 9v + 3 = 0 …………….(3)

Multiplying eq. (2) by 2, we get,

⇒ 6u + 10v + 4 = 0 …………….(4)

Subtracting eq. (3) from (4) we get,

⇒ 6u + 10v + 4 - (6u + 9v + 3) = 0 - 0

⇒ 6u + 10v + 4 - 6u - 9v - 3 = 0

⇒ v + 1 = 0

⇒ v = -1

1y\dfrac{1}{y} = -1

⇒ y = -1

Substituting value of v in eq. (2) we get

⇒ 3u + 5(-1) + 2 = 0

⇒ 3u - 5 + 2 = 0

⇒ 3u - 3 = 0

⇒ 3u = 3

⇒ u = 33\dfrac{3}{3}

⇒ u = 1

1x\dfrac{1}{x} = 1

⇒ x = 1

∴ x = 1 and y = -1

Hence, option 3 is the correct option.

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