I need to solve these two equations using either substitution or elimination 1/4x – 1/2 = 5 3x + 2/3y = -40

Question

I need to solve these two equations using either substitution or elimination
1/4x – 1/2 = 5
3x + 2/3y = -40

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RobertKer 3 years 2021-08-25T10:56:50+00:00 1 Answers 0 views 0

Answers ( )

  1. Philomena
    0
    2021-08-25T10:58:36+00:00
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    Answer:

    y = -15

    x = -10

    Step-by-step explanation:

    1/4x – 1/2 = 5 (1)

    3x + 2/3y = -40 (2)

    Multiply (1) by 4

    1/4x – 1/2 = 5

    1/4x * 4 – 1/2y * 4 = 5 * 4

    4/4x – 4/2y = 20

    x – 2y = 20 (3)

    Multiply (2) by 3

    3x + 2/3y = -40 (2)

    3x * 3 + 2/3y * 3 = -40 * 3

    9x + 6/3y = -120

    9x + 2y = -120 (4)

    x – 2y = 20 (3)

    9x + 2y = -120 (4)

    Using elimination method, Add (3) and (4)

    9x + x = -120 + 20

    10x = -100

    x = -100/10

    x = -10

    Substitute x = -10 into (3)

    x – 2y = 20 (3)

    -10 – 2y = 20

    -2y = 20 + 10

    -2y = 30

    y = 30/-2

    y = -15

    y = -15

    x = -10

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )