Bài `1:`
`a)1/6:(-2/9)=1/6 . (-9/2)=-3/4`
`b)1/3 .(-2/3)-1/2=-2/9-1/2=-4/18-9/18=-13/18`
`c)9/5 . 5/27+1=1/3+1=1/3+3/3=4/3`
Bài `2:`
`a)x. 3/5=-1/2`
`=>x=-1/2:3/5`
`=>x=-1/2 . 5/3=-5/6`
`b)1/2 . x-1/3=[-2]/3`
`=>1/2 .x=[-2]/3+1/3=-1/3`
`=>x=-1/3:1/2`
`=>x=-1/3 .2=-2/3`
Bài 1
\(a,\dfrac{1}{6}:\dfrac{-2}{9}=\dfrac{1}{6}\times\left(-\dfrac{9}{2}\right)=-\dfrac{3}{4}\\ b,\dfrac{1}{3}.\left(-\dfrac{2}{3}\right)-\dfrac{1}{2}=-\dfrac{2}{9}-\dfrac{1}{2}=\dfrac{-2.2-9}{18}=\dfrac{-13}{18}\\ c,\dfrac{9}{5}\times\dfrac{5}{27}+1=\dfrac{9}{27}+1=\dfrac{1}{3}+1=\dfrac{1+3}{3}=\dfrac{4}{3}\)
Bài 2
\(a,x\times\dfrac{3}{5}=-\dfrac{1}{2}\\ \Rightarrow x=\left(-\dfrac{1}{2}\right):\dfrac{3}{5}\\ \Rightarrow x=\left(-\dfrac{1}{2}\right)\times\dfrac{5}{3}\\ \Rightarrow x=-\dfrac{5}{6}\)
\(b,\dfrac{1}{2}x-\dfrac{1}{3}=-\dfrac{2}{3}\\ \Rightarrow\dfrac{1}{2}x=-\dfrac{2}{3}+\dfrac{1}{3}\\ \Rightarrow\dfrac{1}{2}x=-\dfrac{1}{3}\\ \Rightarrow x=\left(-\dfrac{1}{3}\right):\dfrac{1}{2}\\ \Rightarrow x=-\dfrac{2}{3}\)
a)
` 1/6 : -2/9 = 1/6 .( -9/2) = -3/4 `
b)
`1/3 . (-2)/3 - 1/2 `
`=-2/9 - 1/2 `
`= - 4/18 - 9/18 = -13/18`
c)
`9/5 . 5/27 + 1 `
`= 1/3 + 1 = 4/3 `
Bài 2 :
a)
` x . 3/5 = -1/2 `
` x = - 1/2 : 3/5 = - 1/2 . 5/3 `
Vậy `x = -5/6 `
