`1,`
`4/9:(1/15 -2/3)+4/9:(1/11 - 5/22)`
`=4/9 : (-3)/5+4/9 : (-3)/22`
`=4/9 . (-5)/3+4/9 . (-22)/3`
`=4/9(-5/3 - 22/3)`
`=4/9 . (-9)`
`=-4`
`2`
`(x:2+1/3).1/7=-3/8`
`⇔1/2 x +1/3 =-21/8`
`⇔1/2x=-71/24`
`⇔x=-71/12`
Vậy `x=-71/12`
`3`
`(3x+1/5)(x-1/2)=0`
⇔\(\left[ \begin{array}{l}3x+1/5=0\\x-1/2=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-1/15\\x=1/2\end{array} \right.\)
Vậy `x=-1/15;x=1/2`