[tex]\it 1) = \dfrac{2}{21}\cdot\dfrac{21}{4}-3\cdot\dfrac{6}{11}=\dfrac{1}{2}-\dfrac{11}{2}=-\dfrac{10}{2}=-5\\ \\ \\ 2)\ a=4\sqrt3\Rightarrow a^2=16\cdot3=48\\ \\ b=5\sqrt2\Rightarrow b^2=25\cdot2=50\\ \\ \\ 48<50\Rightarrow a^2<b^2 \Rightarrow a<b[/tex]
Remarcă:
a, b sunt numere pozitive.