penyelesaian persamaan |x+7|²- 3 |x+7| = 4

Mapel : Matematika
Kelas : X SMA
Materi : Persamaan Mutlak

Pembahasan :
|x + 7|² - 3|x + 7| = 4
|x + 7|² - 3|x + 7| - 4 = 0

Misal |x + 7| = a
a² - 3a - 4 = 0
(a - 4)(a + 1) = 0

a + 1 = 0
a = -1
|x + 7| = -1
TIDAK MEMENUHI

a - 4 = 0
a = 4
|x + 7| = 4
(x + 7)² = 4²
(x + 7)² - 4² = 0
(x + 11)(x + 3) = 0
x = -11
x = -3

Hp : {-11 , -3}

|x+7|^2 - 3 |x+7|= 4
49-21 = 4
x^2 + 49 -3x - 21 = 4
x^2- 3x + 49-21 =4
x^2- 3x + 28 = 4
x^2- 3x = 4-28
x^2- 3x = -24
x^2 + x = 6
x = √6



maap salah