Question

radical mare ( radical6-radical7) la a 2 + radical mare (radical 6 +radical 7) la a 2 ​

Answer 1

Răspuns:

2√7

Explicație pas cu pas:

|√6-√7|+|√6+√7|=√7-√6+√7+√6=2√7

am tinut cont ca √6<√7, deci √6-√7 <0 deci

|√6-√7|= -(√6-√7)=-√6+√7=√7-√6

pt ca prin definitie

daca x<0, atunci  |x|=-x

si ca √x²=|x| ...si NU  √x²=x

Answer 2

$\it (a\pm b)^2=(b\pm a)^2\\ \\ \\ \sqrt{(\sqrt6-\sqrt7)^2}+\sqrt{(\sqrt6+\sqrt7)^2}= \sqrt{(\ \underbrace{\sqrt7-\sqrt6}_{>0}\ )^2}+\sqrt{(\ \underbrace{\sqrt7+\sqrt6}_{>0}\ )^2}=\\ \\ \\=\sqrt7-\sqrt6+\sqrt7+\sqrt6=2\sqrt7$