Grade 8 - Chapter 4 - SLETV/SPLDV Part 2

Systems of Linear Equation in Two Variables (SLETV)

Sistem Persamaan Linear Dua Variabel (SPLDV)

Standard of Competence :

2.  Understanding System of Linear Equation in Two variables and Using it in problem solving

Memahami SPLDV dan menggunakannya dalam pemecahan masalah

Basic Competence :

2.2 Solving the mathematics problem of problem which has something to do with SLETV  and its estimate.

Menyelesaikan masalah matematika dengan menggunakan Sistem Persamaan Linear Dua Variabel dan perkiraannya.

Learning Objective :

Students are able to determine the root of linear equations system by :

Siswa dapat menentukan penyelesaian dari sistem persamaan linear dengan menggunakan :

1.       Substitution

2.       Elimination

3.       Elimination and Substitution

4.       Graphic methods

Learning Materials :

Determining the root of  SLETV by :

Menentukan peyelesaiandari SPLDV dengan menggunakan :

1.       Substitution

2.       Elimination

3.       Elimination and Substitution

4.       Graphic methods

Resume Materials :

4.2. Solving SLETV

1. Substitution Method
2. Elimination Method
3. Elimination and Subtitution Method
4. Graph Method

1.       Subtitution Method

Substituting means Replacing

Substitusi artinya Mengganti

Example :

Find the solution to the system of equations consisting of x + y = 6 and 2x – y = 0

Tentukan penyelesaian dari persamaan x + y = 6 dan 2x – y = 0

Method 1 : Subtituting x to find the value of y

: Substitusi x untuk mencari nilai y

Method 2: Subtituting y to find the value of x

: Substitusi y untuk mencari nilai x

Answer :

x + y = 6 and 2x – y = 0

Method 1 : Subtituting x

                                x  + y = 6  à x = 6 - y

Subtituting  x = 6 – y  to  2x – y = 0

                  2 (6 - y)  -  y       = 0                          y = 4 subtituting

                  12  – 2y - y         = 0                          x  = 6 - y

                                - 3y         = - 12                     x = 6 - 4

                                     y         = 4                          x = 2

Method 2 : Subtituting y

                                x + y = 6  à y = 6 - x

Subtituting  y = 6 – x  to  2x – y = 0

                2x – (6 - x) = 0                    x = 2 subtituting

                3x - 6     = 0                          y  = 6 - x

                3x           = 6                          y = 6 - 2

                     x         = 2                          y = 4

                  

Exercise :

Find the solution to each of the following systems of equations by subtitution method

Tentukan penyelesaian sistem persamaan berikut dengan metode substitusi

1.       2x = y – 10 and x = 2y + 8

2.       x – 2y = 2 and 3y – 5x = -24

3.       x – y = 3 and 2x + 3y = 16

4.       5x + y = 10 and 4x – 2y = -6

5.       3x – 2y – 7 = 0 and 4x + y – 13 = 0

Reference :

•          Adinawan, Cholik. Sugiyono. 2009. Math for Junior High School 1^st  Semester Grade VIII. Jakarta : Erlangga

•          Agus, Nuniek Avianti, 2008. Mudah Belajar Matematika 2 Untuk Kelas VIII SMP/MTs. Jakarta : BSE Departemen Pendidikan Nasional

•          Dirgen Management of Primary and Scondary Education . 2009. Mathematics Grade VIII Junior High School.  Jakarta : Directorate of Junior High School Development

•          Nuharini, Dewi. Tri Wahyuni. 2008. Matematika Konsep dan Aplikasinya Untuk Kelas VIII SMP dan MTs. Jakarta : BSE Departemen Pendidikan Nasional

•     Nugroho,Heru. Lisda Maesaroh. 2009. Matematika SMP  dan MTs Kelas VIII . Jakarta : BSE Departemen Pendidikan Nasional

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Jika mengcopy file ini ke website anda silahkan cantumkan link www.mathematriks.co.cc di website anda , terima kasih

-== Sky Boy==-                

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