[tex]\it a)\ 3x-2=0 \Rightarrow 3x=2 \Rightarrow x=\dfrac{2}{3},\ \ S=\Big\{\dfrac{2}{3}\Big\} \\ \\ \\ b)\ \dfrac{1}{2}x+1=0|_{\cdot2} \Rightarrow x+2=0 \Rightarrow x=-2\\ \\ \\ c)\ \dfrac{2}{5}x- \dfrac{3}{4}=0\Rightarrow \dfrac{2}{5}x=\dfrac{3}{4}|_{\cdot20} \Rightarrow 8x=15 \Rightarrow x=\dfrac{15}{8}\\ \\ \\ d)\ -0,1x+8=0|_{\cdot10} \Rightarrow -x+80=0 \Rightarrow 80-x=0 \Rightarrow x=80[/tex]
