Question

Aflaati ca : 3(2-$\sqrt{20}$)+$\sqrt{180}$=6

Answer 1

6-3rad20+6rad5=6

6-3*2rad5+6rad5=6

6-6rad5+6rad5=6 (se reduc -6rad5 cu +6rad5 și rămâne 6=6)

Answer 2

$\begin{aligned}3(2-\sqrt{20})+\sqrt{180} &= (6-3\sqrt{20})+\sqrt{9\cdot 20} \\ &= 6-3\sqrt{20}+\sqrt{3^2\cdot 20}\\ &=6-3\sqrt{20}+3\sqrt{20}\\ &=6\,\,\, \checkmark\end{aligned}$