[tex]\it1.\\ \\ a)\ \sqrt{6,4}-\sqrt{8,1}+\sqrt{4,9}=\sqrt{10\cdot0,64}-\sqrt{10\cdot0,81}+\sqrt{10\cdot0,49}=\\ \\ =\sqrt{10}(\sqrt{0,64}-\sqrt{0,81}+\sqrt{0,49})=\sqrt{10}(0,8-0,9+0,7)=0,6\sqrt{10}\\ \\ \\ b)\ 22\sqrt{2}-15\sqrt{2}+17\sqrt{2}-2\sqrt{2}+3\sqrt{2}=\sqrt{2}(22-15+17-2+3)=\\ \\ =\sqrt{2}(42-17)=\sqrt{2}\cdot25=25\sqrt2[/tex]
