nilai mutlak

no. 6

soal

3|2x - 4| = 3|x + 8|

(2x - 4)² - (x + 8)² = 0

(2x - 4 + x + 8)(2x - 4 - (x + 8)) = 0

(3x + 4)(x - 12) = 0

x = -4/3 atau x = 12

HP = {-4/3 , 12}

no. 7

ketinggian sungai = x

|x - 120| < 12

-12 < x - 120 < 12

-12 + 120 < x < 12 + 120

108 < x < 132

interval ketinggian air sungai :

antara 108 cm dan 132 cm

no. 9.

|1/2 x + 6| ≥ 9

1/2 x + 6 ≤ -9 kalikan (2)

x + 12 ≤ -18

x ≤ -18 - 12

x ≤ -30

atau

1/2 x + 6 ≥ 9

x + 12 ≥ 18

x ≥ 18 - 12

x ≥ 6

nilai x :

x ≤ -30 atau x ≥ 6

no. 8

penyusutan panjang = 500 mm = 0,5 m

panjang jembatan

• maksimum = 150 + 0,5 = 150,5 m

• minimum = 150 - 0,5 = 149,5 m

no. 10

|x² - 1| < 3

-3 < x² - 1 < 3

-3 + 1 < x² < 3 + 1

-2 < x² < 4

x² < 4

- √4 < x < √4

-2 < x < 2

HP = {x| -2 < x < 2 , x ∈ R}

no. 11

|2x + 6| - |x - 5| ≥ 10

(2x + 6 - (x - 5)) ≤ -10

x + 11 ≤ -10

x ≤ -21

uji opsi (sebagian)

HP = {x| x ≤ -21 atau x ≥ 3, x ∈ R}