Respuesta :

9514 1404 393

Answer:

  (x, y) = (-3, -6)

Step-by-step explanation:

The coefficients of y are opposites, so adding the two equations will cancel the y-terms.

  (-4x +y) +(-5x -y) = (6) +(21)

  -9x = 27 . . . . . simplify

  x = -3 . . . . . . divide by -9

Now, we can find y.

  -4(-3) +y = 6 . . . . . substitute for x in the first equation

  y = 6 -12 = -6 . . . . subtract 12

The solution is (x, y) = (-3, -6).

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