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9 August, 06:29

Using the linear combination method, what is the solution to the system of linear equations 7x-2y=-20 and 9x+4y=-6?

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Answers (2)
  1. 9 August, 08:40
    0
    (x, y) = ( - 2, 3)

    Step-by-step explanation:

    given the 2 equations

    7x - 2y = - 20 → (1)

    9x + 4y = - 6 → (2)

    multiply (1) by 2 making the coefficients of y equal and opposite

    14x - 4y = - 40 → (3)

    add (2) and (3) term by term

    (9x + 14x) + (4y - 4y) = ( - 6 - 40)

    23x = - 46 (divide both sides by 23)

    x = - 2

    substitute x = - 2 into either (1) or (2) for y

    (2) - 18 + 4y = - 6 (add 18 to both sides)

    4y = 12 (divide both sides by 4)

    y = 3

    solution is ( - 2, 3)
  2. 9 August, 10:09
    0
    The answer would be well, B. (-2,3)
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