Question

calculati 2 √20 - 3 √45 - √2(3 √18 - 2)

Answer 1

$2 \sqrt{20} - 3 \sqrt{45} - \sqrt{2} (3 \sqrt{18} - 2) = \\ \\ 2 \times 2 \sqrt{5} - 3 \times 3 \sqrt{5} - \sqrt{2}(3 \times 3 \sqrt{2} - 2) = \\ \\ 4 \sqrt{5} - 9 \sqrt{5} - \sqrt{2}(9 \sqrt{2} - 2) = \\ \\ (4 \sqrt{5} - 9 \sqrt{5}) - \sqrt{2}(9 \sqrt{2} - 2) = \\ \\ - 5 \sqrt{5} - 18 + 2 \sqrt{2}$

Answer 2

2√20 - 3√45 - √2 · (3√18 - 2) =

= 4√5 - 9√5 - 3√36 + 2√2 =

= 4√5 - 9√5 - 18 + 2√2 =

= -5√5 - 2 · (9 - √2).

/rfd