a) 7 x / 16 = 5 x / 8 - 9 / 24
7 x / 16 - 5 x / 8 = - 3 / 8
7 x / 16 - 10 x / 16 = - 6 / 16 l : 16
7 x - 10 x = - 6
- 3 x = - 6 l : - 3
x = 2
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b) 1 intreg si 1 / 2= ( 1 x 2 + 1 ) / 2 = 3 / 2
3 intregi si 3 / 4 = ( 3 x 4 + 3 ) / 4 = 15 / 4
( 3 / 2 - 15 / 4 ) ( x - 1 ) = 7 - 1 / 4
( 6 / 4 - 15 / 4 ) ( x - 1 ) = 28 / 4 - 1 / 4
( - 9 / 4 ) ( x - 1 ) = 27 / 4
x - 1 = 27 / 4 : ( - 9 / 4 )
x - 1 = - 27 / 4 x 4 / 9
x - 1 = - 3
x = - 3 + 1
x = - 2
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c)
5 x - 4 ( 7 x - 3 ) + 17 = 6 ( 9 x - 7 ) - 3 ( 8 x + 5 ) - 20
5 x - 28 x + 12 + 17 = 54 x - 42 - 24 x - 15 - 20
- 23 x + 29 = 30 x - 77
- 23 x - 30 x = - 77 - 29
- 53 x = - 106 l : ( - 53 )
x = 2
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d)
( 2 x + 9 ) / 3 - 5 ( 2 x + 11 ) / 6 + 9 / 2 = 4 / 3 - ( 3 x + 8 ) / 2
→ aduc fractiile la acelasi numitor comun 6, apoi il elimin impartind relatia la 6
2 ( 2 x + 9 ) - 5 ( 2 x + 11 ) + 27 = 8 - 3 ( 3 x + 8 )
4 x + 18 - 10 x - 55 + 27 = 8 - 9 x - 24
- 6 x - 10 = - 9 x - 16
- 6 x + 9 x = - 16 + 10
3 x = - 6
x = ( - 6 ) : 3
x = - 2
