Câu 6.
2 1/4.( x- 7 1/3)=1,5
9/4.(x-22/3)=3/2
x-22/3=3/2:9/4
x-22/3=2/3
x =2/3+22/3
x =8
Câu 7.
2 2/3.x+8 2/3=3 1/3
8/3.x +26/3 =10/3
8/3.x =26/3-10/3
8/3.x =16/3
x =16/3:8/3
x =2
Câu 8.
3 2/7.x-1/8=2 3/4
23/7.x-1/8 =11/4
23/7.x =11/4+1/8
23/7.x =23/8
x =23/7:23/8
x =7/8
Câu 9.
(2,8x-32):2/3=-90
(14/5x-32):2/3=-90
14/5x-32 =-90.2/3
14/5x-32 =-60
14/5x =-60+32
14/5x =-28
x=-28:14/5
x=10