Page 85 - Matematika-BS-KLS-VII-Licensi
P. 85

Soal 3     Sederhanakanlah.
                              1  6x × 2              2   (-7) × 2y           3  -3a × 4
                                                                                2
                              4  -b × (-9)           5   10 × 0,8x           6      a × 6
                                                                                3



                 Contoh 4    Sederhanakanlah 2(x + 4).
                                                                           Ulasan

                    Cara   hapus tanda kurung dengan menerapkan sifat                                     BAB 2
                                                                           a(b + c) = ab + ac
                           distributif.                                               b + c              │


                 Penyelesaian                                              a      ab         ac           Aljabar
                               2(x + 4)
                             =  2 × x + 2 × 4                                      b         c

                             =  2x + 8       Jawab: 2x + 8




                 Contoh 5     1    (2x + 5) × (-3)                         Ulasan
                               =  2x × (-3) + 5 × (-3)
                                                                           (b + c)a = ab + ac
                               =  -6x – 15
                                                                                        Kelas VII Hlm. 92, 127
                              2    -(7x – 8)

                               =  (-1) × (7x – 8)

                               =  (-1) × 7x + (-1) × (-8)
                               =  -7x + 8


                  Soal 4     Sederhanakanlah.

                              1  5(x + 2)            2   -2(4x + 5)         3  (1 – 6x) × 3
                                                                                2
                              4  (a – 4) × (-6)      5   -(-9x + 8)          6      (9y + 6)
                                                                                  3

                                          x – 5
                             x – 5                × 6
                 Contoh 6              × 6  =     2                          (x – 5) × 6
                               2
                                       = (x – 5) × 3                          2      =  (x – 5) × 3
                                       =3x – 15



                  Soal 5     Sederhanakanlah.
                                3x + 1                                   x – 3
                              1           ×  4                  2  12 ×
                                   2                                      4



                                                                                     Bab 2 Aljabar  79
   80   81   82   83   84   85   86   87   88   89   90