a )
[tex] \boxed{\dfrac{8}{10 } - ( \dfrac{5}{10} + x) = \dfrac{1}{10} } \\ \\ \boxed{ \dfrac{5}{10} + x = \dfrac{8}{10} - \dfrac{1}{10}} \\ \\ \boxed{\dfrac{5}{10} + x = \dfrac{7}{10}} \\ \\ \it\boxed{x = \dfrac{7}{10} - \dfrac{5}{10} = \dfrac{2}{10} }[/tex]
b )
[tex] \boxed{2 - \dfrac{2}{2} - y = \dfrac{1}{2} } \\ \\ \boxed{\dfrac{2}{1} ^{ \cdot2} - \dfrac{2}{2} - y = \dfrac{1}{2} } \\ \\ \boxed{ \dfrac{4}{2} - \dfrac{2}{2} - y = \dfrac{1}{2} } \\ \\ \boxed{ \dfrac{2}{2} - y = \dfrac{1}{2} } \\ \\ \it \boxed{ y = \dfrac{2}{2} - \dfrac{1}{2} = \dfrac{1}{2} }[/tex]
2 )
[tex] \dfrac{3 + x}{9} < 1 \\ \\ 3 + x < 9 \\ \\ x < 9 - 3 = 6 \\ \\ x \:\epsilon 0,1,2,3,4,5[/tex]
[tex] \dfrac{y - 1}{4} < 1 \\ \\ y - 1 < 4 \\ \\ y < 1 + 4 = 5 \\ \\ y = 0...1...2...3...4[/tex]
[tex]1 > \dfrac{1}{8} + \dfrac{z}{8} + \dfrac{2}{8} \\ \\ 1 > \dfrac{3}{8} + \dfrac{z}{8} \\ \\ z < 5 \\ \\ z = 0...1...2...3...4[/tex]
3 )
[tex] \dfrac{8}{10} - ( \dfrac{9}{10} - x) = \dfrac{4}{10} \\ \\ \dfrac{9}{10} - x = \dfrac{8}{10} - \dfrac{4}{10} \\ \\ \dfrac{9}{10} - x = \dfrac{4}{10} \\ \\ x = \dfrac{9}{10} - \dfrac{4}{10} = \dfrac{5}{10}^{ \div 5} = \dfrac{1}{2} [/tex]
4 )
[tex]16 = \dfrac{1}{3} \times x \\ \\ 16 = \dfrac{x}{3} \\ \\ x = 16 \times 3 = 48 \\ \\ 16 = \dfrac{1}{5} \times y \\ \\ 16 = \dfrac{y}{5} \\ \\ y = 16 \times 5 = 80[/tex]
5 )
[tex]( \dfrac{9}{2} + \dfrac{5}{2} - 1) - ( \dfrac{1}{4} + \dfrac{3}{4} + 5) = \\ \\ (\dfrac{14}{2} - 1) - ( \dfrac{4}{4} + 5) = \\ \\ (7 - 1) - (1 + 5) = \\ \\ 6 - 6 = 0[/tex]
2 )
[tex]x - \dfrac{1}{5} = \dfrac{3}{5} \\ \\ x = \dfrac{1}{5} + \dfrac{3}{5} = \dfrac{4}{5} = > c[/tex]
1 )
[tex](2 + \dfrac{2}{5} + \dfrac{3}{5} ) - ( \dfrac{9}{5} + \dfrac{1}{5} ) + \dfrac{24}{5} = \\ \\ ( \dfrac{10}{5} + \dfrac{2}{5} + \dfrac{3}{5} ) - \dfrac{10}{5} + \dfrac{24}{5} = \\ \\ \dfrac{15}{5} - \dfrac{10}{5} + \dfrac{24}{5} = \dfrac{29}{5} [/tex]
