Solve the simultaneous equations 5x + y = 21 x – 3y = 9 x = ________ y = ________

Question

Solve the simultaneous equations

5x + y = 21
x – 3y = 9

x = ________
y = ________

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King 3 years 2021-09-02T07:18:55+00:00 2 Answers 0 views 0

Answers ( )

  1. kimcuc
    0
    2021-09-02T07:20:04+00:00
    Reply

    Answer:

    5x+y=21……equation 1

    x-3y=9……equation 2

    from1:y=21-5x…..equation 3

    substitute y by 21-5x in equation 2

    x-3(21-5x)=9

    x-63+15x=9

    x+15x=9+63

    16x=72(we divide both sides by 16)

    16÷16=72÷16

    therefore x=9/2 or x=4,5

    substitute x by 4,5 or 9/2 in equation 3

    y=21-5(9/2) or y=21-5(4,5)

    y=-3/2 or y=-3/2

    prove

    5(9/2)-3/2=21

    -3/2-3(9/2)=9

  2. Nem
    0
    2021-09-02T07:20:38+00:00
    Reply

    Answer:

    x=9/2

    y= -3/2

    Step-by-step explanation:

    espero que te sirva:)

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