\(c,\dfrac{2}{3}x=0,3-\dfrac{5}{7}\\ \dfrac{2}{3}x=\dfrac{3}{10}-\dfrac{5}{7}\\ \dfrac{2}{3}x=\dfrac{21-50}{70}\\ \dfrac{2}{3}x=-\dfrac{29}{70}\\ x=-\dfrac{29}{70}:\dfrac{2}{3}\\ x=-\dfrac{87}{140}\\ d,\dfrac{3}{4}:x-\dfrac{1}{2}=\dfrac{3}{7}\\ \dfrac{3}{4}:x=\dfrac{3}{7}+\dfrac{1}{2}\\ \dfrac{3}{4}:x=\dfrac{6+7}{14}\\ \dfrac{3}{4}:x=\dfrac{13}{14}\\ x=\dfrac{3}{4}:\dfrac{13}{14}\\ x=\dfrac{21}{26}\)
c: =>2/3x=3/10-5/7=-29/70
=>x=-87/140
d: =>3/4:x=3/7+1/2=13/14
=>x=21/26
`2/3 x + 5/7=0,3`
`2/3 x + 5/7=3/10`
`2/3 x =3/10 - 5/7`
`2/3 x = -29/70`
`x=-29/70 : 2/3`
`x=-29/70 . 3/2`
`x= -87/140`
`----------`
`3/4 : x-0,5=3/7`
`3/4 : x-1/2=3/7`
`3/4 : x= 3/7+1/2`
`3/4 : x= 13/14`
`x=3/4 : 13/14`
`x=21/26`
