Question

a) 2√5(√125-3√5)
b) (4√24+2√54)(-0,5√6)
c) 3supra lui 4 x+ 2supra lui 9

Answer 1

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