[tex]\displaystyle a).x+ \frac{7}{3} = \frac{2}{9} \Rightarrow 9x+7 \cdot 3=2 \Rightarrow 9x+21=2 \Rightarrow 9x=2-21 \Rightarrow \\ \\ \Rightarrow 9x=-19 \Rightarrow x=- \frac{19}{9} \\ \\ b). \frac{4}{5}x- \frac{3}{10} x=-3 \Rightarrow 4x \cdot 2-3x=-3 \cdot 10 \Rightarrow 8x-3x=-30 \Rightarrow \\ \\ \Rightarrow 5x=-30 \Rightarrow x=- \frac{30}{5} \Rightarrow x=-6 [/tex]
[tex]\displaystyle c). \frac{x}{3}+5- \frac{x}{9}- \frac{x}{27} - \frac{2}{3} = \frac{1}{9} \Rightarrow 9x+5 \cdot 27-3x-x-2 \cdot 9=1 \cdot 3 \Rightarrow \\ \\ \Rightarrow 9x+135-3x-x-18=3 \Rightarrow 9x-3x-x=3-135+18 \Rightarrow \\ \\ \Rightarrow 5x=-114 \Rightarrow x=- \frac{114}{5} [/tex]
