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Va rog repede dau coroana |7x+2|-6=4​

Răspuns :

|7x+2|-6=4

|7x+2|=4+6

|7x+2|=10

1. 7x+2= -10

7x= -10-2

7x= -12

x= -12/7

2. 7x+2=10

7x=10-2

7x=8

x=8/7

x∈{-12/7,8/7}

|7x+2| - 6 = 4

|7x+2| = 4 + 6 = 10

|7x+2| este egal cu:

[tex] = > 7x + 2 \: dacă \: 7x + 2 \geqslant 0[/tex]

[tex] = > - 7x - 2 \: dacă \: 7x + 2 < 0[/tex]

Cazul 1: 7x+2 >= 0

[tex]=> x \geqslant \frac{ - 2}{7} [/tex]

7x+2 = 10

7x = 10 - 2 = 8

[tex]x = \frac{8}{7} \geqslant - \frac{2}{7} (adevărat)[/tex]

.

Cazul 2: 7x+2 < 0

[tex]=> x < \frac{ - 2}{7} [/tex]

-7x - 2 = 10

-7x = 10 + 2 = 12

[tex]x = - \frac{12}{7} < - \frac{2}{7} (adevărat)[/tex]