Question

calcule o valor das expressões
a)-76-(7-18)+[70-(7-81)]
B) -(-2)-7-[-18+4+(7-15)]
C)-{20-(2-10) +[-30-(-70)]}
D) {[(73-64)+20]-(40-31)}+(-3)
por favor me ajudem

Answer 1

a)
= - 76 - (7 - 18) + [70 - (7 - 81)]
= - 76 - ( - 11) + [ 70 - ( - 74)]
= - 76 + 11 + [ 70 + 74]
= - 65 + 144
= 144 - 65
=  79

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B)
= - ( - 2) - 7 - [- 18 + 4 + (7 - 15)] 
= 2 - 7 - [ - 14 + ( - 8)]
=  - 5 - [ - 14 - 8]
= - 5 - [ - 22]
= - 5 + 22
= 17

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C)
= - {20 - (2 - 10) + [ - 30 - (-70)]}
= - { 20 - ( - 8) + [ - 30 + 70]}
= - { 20 + 8 + [ 40]}
= - { 28 + 40}
= - { 68}
= - 68
 
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D)
= {[(73 - 64) + 20] - (40 - 31)} + (- 3)
= {[ 9 + 20] - 9} - 3
= { 29 - 9} - 3
= 20 - 3
= 17