1, D
2, D
3, C
4, C
5, B
6, C
7, A
8, C
9, D
10, D
11, D
12, C
Bài 2:
a, 2x = 1/6 + 2/9
=> 2x = 7/18
=> x = 7/36
Vậy x = 7/36
b, 0,25x + 1/3/4x = 6
=> (0,25 + 1/3/4) .x = 6
=> 2x = 6
=> x = 3
Vậy x = 3
c, 3.2^(2x+1) +1/2 = 49/2
=> 3.2^(2x+1) = 24
=> 2^(2x+1) = 8
Mà 2³ = 8
=> 2^(2x+1)=2³
=> 2x+1 = 3
=> 2x=2
=> x= 1
Vậy x =1
ỦNG HỘ MIK NHA!!!!!!!!!!! CHÚC BN HỌC TỐT :))))))))))))
