y = 2x + 4 and y = 2x – 8 Solve the systems by substitution

Question

y = 2x + 4
and
y = 2x – 8

Solve the systems by substitution

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Minh Khuê 5 years 2021-09-02T22:51:48+00:00 2 Answers 30 views 0

Answers ( )

  1. Delwyn
    0
    2021-09-02T22:53:08+00:00
    Reply

    Answer:

    -x – y – z  = -8   ……..      (1a)

    -4x + 4y +5z = 7     …..   (2a)

    2x + 2x =  4   ……….       (3a)

    since (3a) a is an equation solely in x make x the subject of the equation

      2 ( x + x) = 4

     divide both sides by 2

          (x + x)  = 2

                2x  = 2

                  x  =  1  …….  (3b)

      substitute x in (3b) for x in (1a)

              -(1) – y – z  = -8  

        make y the subject of the equation

                  -y – z  =  -8 + 1

                        -y =  -7 + z

                         y = 7 – z  ….. (1b)

     substitute y in (1b) for y in (2a) as well as the value of x ( x= 1)

            -4(1)+ 4( 7 – z ) +5z = 7

           – 4 + 28 – 4z + 5z  = 7

                  -24 + z  = 7

                           z  = 7 + 24

                           z  = 31

    By using (1a) solve for y

              -(1) – y – (31)= -8          

              -1  – y – 31 = -8        

                            y = -1 – 31 + 8

                            y = -24

     

    ∴ the solutions of the system are  x = 1 ; y = -24 ; z = 31  

    Hope this helps!!!!!!!

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  2. thienthanh
    0
    2021-09-02T22:53:20+00:00
    Reply

    Answer:Tiger Algebra gives you not only the answers, but also the complete step by step method for solving your equations 2x-y=8;2x+y=4 so that you

    Step-by-step explanation:

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