Ответ:

[tex]-\frac{9}{10}[/tex]

Объяснение:

[tex]\sqrt{1\frac{4}{5}}\cdot\sqrt{0,2}-\sqrt{2,25}=\sqrt{\frac{9}{5}\cdot \frac{2}{10}}-\sqrt{2\frac{1}{4}}=\sqrt{\frac{9}{25}}-\sqrt{\frac{9}{4}}=\frac{3}{5}-\frac{3}{2}=\frac{6}{10}-\frac{15}{10}=-\frac{9}{10}[/tex]