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16 August, 09:48

Solve this system of linear equations. Separate

the x - and y-values with a comma.

7x + 9y = 10

-2x + 6y = - 20

+5
Answers (1)
  1. 16 August, 12:04
    0
    (4, - 2)

    Step-by-step explanation:

    Given the 2 equations

    7x + 9y = 10 → (1)

    - 2x + 6y = - 20 → (2)

    Multiplying (1) by 2 and (2) by 7 and adding will eliminate the x term

    14x + 18y = 20 → (3)

    - 14x + 42y = - 140 → (4)

    Add (3) and (4) term by term

    (14x - 14x) + (18y + 42y) = (20 - 140), that is

    60y = - 120 (divide both sides by 60)

    y = - 2

    Substitute y = - 2 into either of the 2 equations and solve for x

    Substituting in (1)

    7x + 9 ( - 2) = 10

    7x - 18 = 10 (add 18 to both sides)

    7x = 28 (divide both sides by 7)

    x = 4

    Solution is (4, - 2)
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