Respuesta :

mhanifa

Answer:

  • B. (6, -3)

Step-by-step explanation:

Given the system of equations:

  • 2x - 3y = 21  
  • 5x + 4y = 18

Multiply the first equation by 4 and the second one by 3 and add up:

  • 8x - 12y + 15x + 12y = 21*4 + 18*3
  • 23x = 138
  • x = 138/23
  • x = 6

Find y:

  • 2*6 - 3y = 21
  • 3y = 12 - 21
  • 3y = -9
  • y = -3
  • 2x-3y=21--(1)
  • 5x+4y=18--(2)

Eq(1)×5 and (2)×2

  • 10x-15y=105
  • 10x+8y=36

Subtracting

  • -23y=69
  • y=-3

On putting in eq(1)

  • x=6

(6,-3) is the soln

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