[tex]2 \sqrt{5} ( \sqrt{125} - 3 \sqrt{5} = 2 \sqrt{5} (5 \sqrt{5} - 3 \sqrt{5} ) = 2 \sqrt{5} \times 2 \sqrt{5} = 4 \sqrt{25} = 20[/tex]
[tex](4 \sqrt{24} + 2 \sqrt{54} )( - 0.5 \sqrt{6} ) = (8 \sqrt{6} + 6 \sqrt{6} )( - 0.5 \sqrt{6} ) = 14 \sqrt{6} ( - 0.5 \sqrt{6} ) = - 7 \sqrt{36} = - 7 \times 6 = - 42[/tex]
[tex] \frac{3}{4} + \frac{2}{9} = \frac{27 + 8}{36} = \frac{35}{36} [/tex]
