Помогите пожалуйста!!! Баллы.

[latex]1,2\ \textless \ x\ \textless \ 2,4\\\\1,5\ \textless \ y\ \textless \ 2,7\\\\a)\; \; 2,4\ \textless \ 2x\ \textless \ 4,8\; \; \; ;\; \; \; 3,0\ \textless \ 2y\ \textless \ 5,4\\\\5,4\ \textless \ 2x+2y\ \textless \ 10,2\\\\b)\; \; 1,8\ \textless \ xy\ \textless \ 6,48\; \; \; ; \; \; 9\ \textless \ 5xy\ \textless \ 32,4\\\\c)\; \; 0,6\ \textless \ 0,5x\ \textless \ 1,2\; \; ;\; \; \; -0,27\ \textless \ -0,1y\ \textless \ -0,15\\\\0,33\ \textless \ 0,5x-0,1y\ \textless \ 1,05\\\\d)\; \; \frac{1}{2,4} \ \textless \ \frac{1}{x} \ \textless \ \frac{1}{1,2} \; \; \to \; \; \frac{10}{24} \ \textless \ \frac{1}{x} \ \textless \ \frac{10}{12} \; \; \to \; \; \; \frac{5}{12}\ \textless \ \frac{1}{x}\ \textless \ \frac{5}{6} \\\\ \frac{10}{27}\ \textless \ \frac{1}{y}\ \textless \ \frac{2}{3} \\\\ \frac{5}{12}+\frac{10}{27}\ \textless \ \frac{1}{x}+\frac{1}{y} \ \textless \ \frac{5}{6}+\frac{2}{3}[/latex] [latex] \frac{85}{108}\ \textless \ \frac{1}{x}+\frac{1}{y}\ \textless \ \frac{3}{2} \\\\2)\; \; 2,4\ \textless \ \sqrt6\ \textless \ 2,5\; \; ;\; \; \; 2,6\ \textless \ \sqrt7\ \textless \ 2,7\\\\\sqrt{28}-\sqrt{42}=2\sqrt7-\sqrt6\cdot \sqrt7\\\\5,2\ \textless \ 2\sqrt7\ \textless \ 5,4\; \; \; ;\; \; \; 6,24\ \textless \ \sqrt6\cdot \sqrt7\ \textless \ 6,75\; \; ;\\\\-6,75\ \textless \ -\sqrt6\cdot \sqrt7\ \textless \ -6,24\\\\-1,55\ \textless \ 2\sqrt7-\sqrt6\cdot \sqrt7\ \textless \ -0,84[/latex]