=\(2\left|2-\sqrt{5}\right|\)

=\(2.\left(\sqrt{5}-2\right)\)

=\(2\sqrt{5}-4\)

P = \(1\)- (\(3\sqrt{5}\) -\(2\)\(\sqrt{5}\) -\(\sqrt{3}\) )(\(2\sqrt{5}-3\sqrt{5}-\sqrt{3}\))

= 1- (\(\sqrt{5}-\sqrt{3}\) )(\(-\sqrt{5}-\sqrt{3}\) )

= 1+ ( \(\sqrt{5}-\sqrt{3}\) )( \(\sqrt{5}+\sqrt{3}\) )

= 1+ (5-3)

= 3

= ( 2\(\sqrt{3}\) + 5\(\sqrt{3}\) + 3\(\sqrt{3}\) ):\(\sqrt{15}\)

=10\(\sqrt{3}\) :( \(\sqrt{3}\times\sqrt{5}\) )

=2\(\times\)5\(\times\)\(\sqrt{3}\) : \(\sqrt{3}\) :\(\sqrt{5}\)

=2\(\sqrt{5}\)

SO₂+Na₂SO₃\(\rightarrow\)Na₂S₂O₅

bạn ơi KD không song song được với AD

Cho a²+b²=(a+b+c)²

CMR: \(\dfrac{\left(a-c\right)^2+a^2}{\left(b-c\right)^2+b^2}\)=\(\dfrac{a-c}{b-c}\)

A=\([\)(x+y)(x+4y)\(][\)(x+2y)(x+3y)]+y⁴

=(x²+4xy+xy+4y²)(x²+3xy+2xy+6y²)+y⁴

=(x²+5xy+4y²)(x²+5xy+6y²)+y⁴

=(x²+5xy+5y²-y²)(x²+5xy+5y²+y²)+y⁴

=(x²+5xy+5y²)²-y⁴+y⁴

=(x²+5xy+5y²)²

vậy A là số chính phương vs \(\forall\) x,y\(\in\)R

A +B=1