Penjelasan dengan langkah-langkah:

3. (1) 3x + 18 = x + 2

3x - x = 2 - 18

2x = -16

x = -16/2

x = -8.

(2) 6x - 2x + 9 = 11

4x = 11 - 9

4x = 2

x = 2/4

x = 1/2.

(3) 9x - 6x - 10 = 2

3x = 2 + 10

3x = 12

x = 12/3

x = 4.

(4) 7x - 14 = 4x - 20

7x - 4x = - 20 + 14

3x = - 6

x = -6/3

x = -2.

4. (1) 0,4x + 0,2x = -1,8

4x + 2x = -18 (dikali 10)

6x = -18

x = -18/6

x = -3.

(2) 7x - 10 = 3x + 20 (dikali 10)

7x - 3x = 20 + 10

4x = 30

x = 30/4

x = 7,5

(3) 13x = 7x - 30 (dikali 100)

13x - 7x = - 30

6x = - 30

x = -30/6

x = -5.

(4) 75x - 200 = 50x (dikali 100)

75x - 50x = 200

25x = 200

x = 200/25

x = 8.

5. (1) 4x - 2 = x (dikali 2)

4x - x = 2

3x = 2

x = 2/3.

(2) 3x - 2 = 2x + 18 (dikali 6)

3x - 2x = 18 + 2

x = 20.

(3) x - 8 = -15 (dikali 3)

x = -15 + 8

x = -7.

(4) 3(x + 5) = 6(3x - 1) (dikali silang)

3x + 15 = 18x - 6

15 + 6 = 18x - 3x

21 = 15x

x = 21/15

x = 7/5.

Kunci pengerjaan soal yang seperti ini :

• Gunakan teknik kali pelangi apabila menemukan kurung.
• Apabila berbentuk pecahan, kalikan kedua ruas dengan KPK dari penyebut pecahan - pecahan tersebut.

Semoga membantu.