Respuesta :

Answer:

  • Option D

Step-by-step Solution:

  • => x + 4y = 5

            5x + 6y = 7

  • => 3(x + 4y = 5)

            2(5x + 6y = 7)

  • => 3x + 12y = 15

            10x + 12y = 14

  • => 3x + 12y = 15

            -10x - 12y = -14

  • => -7x = 1
  • => x = -1/7
  • => x + 4y = 5
  • => -1/7 + 4y = 5
  • => 4y = 5 + 1/7
  • => 4y = 35/7 + 1/7
  • => 4y = 36/7
  • => y = 9/7
  • => 3x + 5y
  • => 3(-1/7) + 5(9/7)
  • => -3/7 + 45/7
  • => 42/7
  • => 6

Hence, Option D is correct.

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