Question

Daca a =
$\sqrt{6}$
si b=
$\sqrt{3}$
$- \sqrt{2}$
atunci, b²+2 a este egal cu
a)1+2
$\sqrt{6}$
b)5;
c)2;
d)4.​

Answer 1

Răspuns: 5 → Varianta b)

Explicație pas cu pas:

$\bf a = \sqrt{6}$

$\bf b = \sqrt{3} -\sqrt{2}$

$\bf b^{2}+2a =\Big(\sqrt{3} -\sqrt{2}\Big)^{2}+2\sqrt{6} =\Big(\sqrt{3}\Big)^{2}-2\sqrt{3}\cdot\sqrt{2} +\Big(\sqrt{2}\Big)^{2}+2\sqrt{6} =$

$\bf 3-2\sqrt{6}+2+2\sqrt{6} =5-2\sqrt{6}+2\sqrt{6} =\red{\underline{~5~}}$

Answer 2

Răspuns:

a=√6

b=√3-√2

b²+2a=(√3-√2)²+2·√6=√3²+√2² -2√2·√3+2√6=5 - 2√6+2√6=5