how do you work out this equation? solve simultaneous equations by substitution x + y =3 5x + y = 15

Question

how do you work out this equation?
solve simultaneous equations by substitution
x + y =3
5x + y = 15

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Thu Cúc 1 month 2021-08-13T20:09:41+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-08-13T20:11:17+00:00

    Answer:

    Step-by-step explanation:

    x+y=3

    5x+y = 15

    I method:

    y = 3 – x. substitute this in 2nd equation

    5x + (3-x) = 15

    5x + 3 – x = 15

    4x = 12

    x=3

    y=0

    II method:

    subtracting 2nd equation and 1st equation we get

    4x +0y = 12

    x = 3

    y = 0

    0
    2021-08-13T20:11:18+00:00

    Step-by-step explanation:

    x + y = 3. => y = 3 – x

    5x + y = 5x + (3 – x) = 15.

    => 4x + 3 = 15

    => 4x = 12, x = 3.

    Therefore y = 3 – (3) = 0.

    The solutions are x = 3 and y = 0.

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