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7. Rezolvați următoarele inecuații, unde x aparține Z
a) 3(2x + 9) < 15
b) 4(5x + 8) > 12
c) 7(1 - 2x) <_ -21

Coroana!!!

Răspuns :

Alexdapaxbox

a) 2x+9< 15-3

2x +9 < 12

2x < 12-9

2x< 3

b) 5x+8> 12-4

5x >8-8

5x > 0

c) 1-2x < -21-7

2x <-29

Dariageorgianaboghia

Răspuns:

a) 3 (2x + 9) < 15

6x + 27 < 15

6x < 15| -27

6x < -12| :6

x < 2

x = {1,0,-1 -2,-3,...}

b) 4 (5x + 8) > 12

20x + 32 > 12| -32

20x > -20| :20

x > 1

x = {2,3,4,5,...}

c) 7 (1 - 2x) <_ -21

7 - 14x <_ -21| -7

-14x <_ 14| :14

x <_ 1

x = {1,0,-1,-2,-3,...}

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