Đáp án:
Giải thích các bước giải:
a) 6,5 - 9/4:|x+1/3|=2
⇒9/4:|x+1/3|=6,5-2
⇒9/4:|x+1/3|=4,5
⇒|x+1/3|=9/4:4,5
⇒|x+1/3|=1/2
⇒x+1/3=1/2 hay x+1/3=-1/2
⇒x=1/6 hay x=-5/6
vậy x=1/6,x=-5/6
b) 21/5+3|x/4-2/3|=6
⇒3|x/4-2/3|=6-21/5
⇒3|x/4-2/3|=9/5
⇒|x/4-2/3|=9/5:3
⇒|x/4-2/3|=5/3
⇒x/4-2/3=5/3 hay x/4-2/3=-5/3
⇒x=28/3 hay x=-4
vậy x=28/3,x=-4
c)
11/4+3/2:|4x-1/5|=7/2
⇒ 3/2:|4x-1/5| = 7/2 - 11/4
⇒ 3/2:|4x-1/5| = 3/4
⇒ |4x-1/5| = 3/2 : 3/4
⇒|4x-1/5| = 2
⇒4x-1/5=2 hay 4x-1/5=-2
⇒x=11/20 hay x=-9/20
vậy x=11/20 x=-9/20
d) 15/4-2,5:|3/4x+1/2|=3
15/4 - 2,5:|3/4x + 1/2| = 3
2,5:|3/4x + 1/2| = 15/4 - 3
2,5:|3/4x + 1/2| = 3/4
|3/4x + 1/2| = 2,5 : 3/4
|3/4x + 1/2| = 10/3
⇒3/4x + 1/2 = 10/3 hay 3/4x + 1/2 = -10/3
3/4x = 10/3 - 1/2 3/4x = -10/3 - 1/2
3/4x = 17/6 3/4x = -23/6
