a)
[tex](1\frac{5}{9}+1\frac{1}{3}):1\frac{4}{9}-\frac{1}{2}=(1\frac{5}{9}+1\frac{3}{9}):\frac{13}{9}-\frac{1}{2}=\\\\=2\frac{8}{9}:\frac{13}{9}-\frac{1}{2}=\frac{26}{9}\cdot\frac{9}{13}-\frac{1}{2}=2-\frac{1}{2}=2-0,5=\boxed{1,5}[/tex]
b)
[tex]2,6\cdot3+(7,8-4,3):0,7=\\\\=7,2+3,5:0,7=7,2+35:7=\\\\=7,2+5=\boxed{12,2}[/tex]
