a)
\sqrt{(1\frac{1}{4})^2-1}+\sqrt{1+\frac{7}{9}}=\sqrt{(\frac{5}{4})^2-1}+\sqrt{1\frac{7}{9}}=\sqrt{\frac{25}{16}-\frac{16}{16}}+\sqrt{\frac{16}{9}}=
=\sqrt{\frac{9}{16}}+\frac{4}{3}=\frac{3}{4}+\frac{4}{3}=\frac{9}{12}+\frac{16}{12}=\frac{25}{12}=2\frac{1}{12}
b)
\frac{6\frac{3}{7}-5\frac{5}{7}*1,8}{1:(\frac{1}{2}+\frac{1}{6})}=\frac{5\frac{10}{7}-5\frac{5}{7}*\frac{18}{10}}{1:\frac{3+1}{6}}=\frac{\frac{5}{7}*\frac{9}{5}}{1*\frac{6}{4}}=
=\frac{\frac{9}{7}}{\frac{3}{2}}=\frac{9}{2}*\frac{2}{3}=3
c)
(-4)^2-(\sqrt5)^3-(-3\sqrt2)^2=16-(5^{\frac{1}{2}})^3-9*2=16-(\sqrt5)^2*\sqrt5-18=
=16-5\sqrt5-18=-2-5\sqrt5