( tfvxhvxjhdbvxjdvjdv0)

Đáp án+Giải thích các bước giải:

 `a)`

`\frac{x}{3}=\frac{-10}{6}`

`=>x.6=3.(-10)`

`=>6x=-30`

`=>x=(-30):6`

`=>x=-5`

Vậy `x=-5`

`b)`

`\frac{-8}{x}=\frac{-9}{15}` `(đk:x\ne0)`

`=>x.(-9)=(-8).15`

`=>x.(-9)=-120`

`=>x=(-120):(-9)`

`=>x=40/3`

Vậy `x=40/3`

`c)`

`\frac{2,7}{0,9}=\frac{-8}{x}` `(đk:x\ne0)`

`=>2,7.x=0,9.(-8)`

`=>2,7.x=-7,2`

`=>x=(-7,2):2,7`

`=>x=-8/3`

Vậy `x=-8/3`

`d)`

`4/9=\frac{x}{12}`

`=>9.x=4.12`

`=>9.x=48`

`=>x=48/9`

`=>x=16/3`

Vậy `x=16/3`

Bài `3:`

`a)`

`12/7:3/14=x:2/5`

`=>x:2/5=12/7. 14/3`

`=>x:2/5=8`

`=>x=8. 2/5`

`=>x=16/5`

Vậy `x=16/5`

`b)`

`2 5/6: 2/5=3,4:x`

`=>3,4:x=17/6: 2/5`

`=>3,4;x=17/6. 5/2`

`=>3,4:x=85/12`

`=>x=3,4:85/12`

`=>x=12/25`

Vậy `x=12/25`

`c)`

`\frac{-5}{9}: 1 8/11=\frac{-11}{19}:x`

`=>-11/19:x=(-5/9):19/11`

`=>-11/19:x=55/171`

`=>x=(-11/19):55/171`

`=>x=-9/5`

Vậy `x=-9/5`

`d)`

`1 1/2: 4/3=x:1/15`

`=>x:1/15=3/2:4/3`

`=>x:1/15=3/2. 3/4`

`=>x:1/15=9/8`

`=>x=9/8. 1/15`

`=>x=3/40`

Vậy `x=3/40`