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Va rog, repede..........

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Răspuns :

Maverickarcher

a) 21x = 42

x = 42/21

x = 2 € lN si € Z

Verificare: 21*2 = 42

42 = 42 (A)

b) -2x = 16

x = 16/(-2)

x = -8 € Z, dar nu apartine lui lN

Verificare: -2*(-8) = 16

16 = 16 (A)

c) -6x + 17 = 5

-6x = 5-17

-6x = -12

x = 12/6

x = 2 € Z, € lN

Verificare : -6*2 = 5-17

-12 = -12 (A)

d) -x - x = -14-14

-2x = -28

x = -28/(-2)

x = 14 € Z, € lN

Verificare: 14-14 = 14-14

0 = 0 (A)

Cocirmariadenis

a)  

21 x - 42 = 0

21 x = 42

x = 42 : 21

x = 2 ∈ N

Verific:  21 × 2 - 42 = 42 - 42 = 0

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b)

- 2 x = 16

x = 16 : ( - 2 )

x = - 8 ∈ Z

Verific:   - 2 × ( - 8 ) = 16

___________________________

c)  

( - 2 ) ·  3 x + 17 = 5

- 6 x = 5 - 17

- 6 x = - 12

x = ( - 12 ) : ( - 6 )

x = 2

Verific:   ( - 2 ) · 3 · 2 + 17 = - 12 + 17 = 5

_______________________________

d)  

14 - x = x - 14

- x - x = - 14 - 14

- 2 x = - 28

x = - 28 : ( - 2 )

x = 14

Verific:   14 - 14 = 14 - 14 = 0

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