a/ 58.32 + 58.68 - 800 = 116.00 - 800 = -684.00
b/ 12020 + 280 : [55 - (7 - 4)3] = 12020 + 280 : [55 - 3*3] = 12020 + 280 : [55 - 9] = 12020 + 280 : 46 = 12020 + 6.09 = 12026.09
c/ (96 - 19 - 45) - (55 + 96 - 119) = 32 - 72 = -40

Bài 2:
a/ 7x - 70 = 105
7x = 105 + 70
7x = 175
x = 175/7
x = 25

b/ 85 - 5(4 + x) = 15
85 - 20 - 5x = 15
-5x = 15 - 85 + 20
-5x = -50
x = -50/-5
x = 10

c/ (-44)(x + 20) = -440
-44x - 880 = -440
-44x = -440 + 880
-44x = 440
x = 440/-44
x = -10