a) x + 5 = 2021 - (12 - 7)
x + 5 = 2021 - 5
x + 5 = 2016
x = 2016 - 5
x = 2011
Vậy x = 2011
b) -8.|x - 3| = -48
|x - 3| = -48 : (-8)
|x - 3| = 6
x - 3 = 6 hoặc x - 3 = -6
* x - 3 = 6
x = 6 +3
x = 9
* x - 3 = -6
x = -6 + 3
x = -3
Vậy x = 9 hoặc x = - 3
c) (102 - 2x) : 2^5 = 2020^0 + 1
(102 - 2x) : 32 = 1 + 1
(102 - 2x) : 32 = 2
102 - x = 2.32
102 - x = 64
x = 102 - 64
x = 38
Vậy x = 38
d) 15 - 4x = 25 - 3x
-4x + 3x = 25 - 15
-x = 10
x = -10
Vậy x = -10