Răspuns
Explicație pas cu pas:
16) a)
a = ( + 5 ) - [ - 7 - ( - 2 ) ]
a = 5 - ( - 7 + 2 )
a = 5 - ( - 5 )
a = 5 + 5
a = 10
b = ( + 5 ) - ( - 7 ) + ( - 2 )
b = 5 + 7 - 2
b = 12 - 2
b = 10
=> a = b = 10
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b)
a = ( - 10 ) - [ - 10 - ( - 10 ) ]
a = - 10 - ( - 10 + 10 )
a = - 10 - 0
a = - 10
b = ( - 10 ) - ( - 10 ) + ( - 10 )
b = - 10 + 10 - 10
b = - 10
=> a = b = - 10
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c)
a = ( - 15 ) - [ + 6 - ( - 21 ) ]
a = - 15 - ( 6 + 21 )
a = - 15 - 27
a = - 42
b = ( - 15 ) - ( + 6 ) + ( - 21 )
b = - 15 - 6 - 21
a = - 21 - 21
a = - 42
==> a = b = - 42
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d)
a = ( + 5 ) - [ - 5 - ( - 7 ) ]
a = 5 - ( - 5 + 7 )
a = 5 - ( + 2 )
a = 5 - 2
a = 3
b = ( + 5 ) - ( - 5 ) + ( - 7 )
b = 5 + 5 - 7
b = 10 - 7
b = 3
==> a = b = 3
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17).
( - 8 ) + ( + 3 ) + ( - 2 ) = - 8 + 3 - 2 = - 5 - 2 = - 7
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( - 8 ) + ( + 5 ) + a = - 7
- 3 + a = - 7
a = - 7 - ( - 3 )
a = - 7 + 3
a = - 4
_____________
( + 3 ) + b + ( - 10 ) = - 7
b = - 7 + 10 - 3
b = 3 - 3
b = 0
___________________
+ 5 + 0 + c = - 7
c = - 7 - 5
c = - 12
___________________
- 4 + ( - 10 ) + d = - 7
- 14 + d = - 7
d = - 7 + 14
d = 7
________________________
b) a + b + c + d = - 4 + 0 + ( - 12 ) + 7= - 16 + 7 = - 9
- 8 + b + d = - 8 + 0 + 7 = - 1
a + b + ( - 2 ) = - 4 + 0 - 2 = - 6
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19)
- 6 =( - 10) - ( - 4 ) = - 10 + 4 → diferenta a doua numere intregi negative
- 6 = ( + 2 ) - ( + 8 ) = 2 - 8 → diferenta a doua numere intregi pozitive
- 6 = ( - 5 ) - ( + 1 ) = - 5 - 1 → diferenta a doua numere intregi cu semne contrare
