#Ngocbich007
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a) 110 - 10 . ( 3x - 11 ) = 10
10 . ( 3x - 11 ) = 110 - 10 = 100
3x - 11 = 100 : 10 = 10
3x = 10 + 11 = 21
x = 21 : 3 = 7
Vậy x = 7
b) 120 : 20 + 2 . ( 12 - 2x ) = 10
6 + 2 . ( 12 - 2x ) = 10
2 . ( 12 - 2x ) = 10 - 6 = 4
12 - 2x = 4 : 2 = 2
2x = 12 - 2 = 10
x = 10 : 2 = 5
Vậy x = 5