Question

Se considera numerele reale :
$x = (3 \sqrt{20} - 2 \sqrt{45} + \sqrt{405}) \times 0.(3)$
Am nevoie doar de x care cica trebuie sa dea
$3 \sqrt{5}$
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Answer 1

$x = (3 \sqrt{20} - 2 \sqrt{45} + \sqrt{405} ) \times 0.(3) = (6 \sqrt{5} - 6 \sqrt{5} + 9 \sqrt{5}) \times \frac{3}{9} = 9 \sqrt{5} \times \frac{3}{9} = 3 \sqrt{5}$