Giúp Mình với Hepl

Đáp án:

 Bài 2: 

a,  (2/3).x=2/7

⇔ x=2/7÷2/3

⇔ x=3/7

 b, x÷8/13=13/7

⇔ x=13/7.8/13

⇔ x=8/7

c, 3/2÷x=7/4

⇔ x=3/2÷7/4

⇔ x=6/7

d, x-1/24=-1/8+5/6

⇔ x=-1/8+5/6+1/24

⇔ x=3/4

(e*) 2/9-7/8.x=1

⇔ -7/8.x=1-2/9

⇔-7/8.x=7/9

⇔ x=7/9÷(-7/8)

⇔ x=-8/9

e, 5/8-x=1/9-(-5/4)

⇔ -x=1/9+5/4-5/8

⇔ -x=53/72

⇔ x=-53/72

f,  1/24+x=-1/8+5/6

⇔ x=-1/8+5/6-1/24

⇔ x=2/3

g, -5/8÷x-1/2=-4/3.15/16

⇔ -5/8÷x-1/2=-5/4

⇔ -5/8÷x=-5/4+1/2

⇔-5/8÷x=-3/4

⇔ x=-5/8÷(-3/4)

⇔ x=5/6

Bài 3:

a, 16/15.(-5/14).54/24.56/21=-16/7 ( chi tiết thì tự làm nha mik k có thời gian)

b, 7/3.(-5/2).15/21.(4/-5)=10/3

c, 5. 7/5= 7

b. 3/4.7/9+1/4.7/9=7/9

d, 1/7.5/9+5/9.1/7+5/9.3/7=25/63

e, 4.11.3/4.9/121=27/11

f, 31/23-(7/32+8/23)=25/32

b. 38/45-(8/45-17/51-3/11)=14/11

c, (1/3+12/67+13/41)-(79/67-28/41)=1/3