a: \(=2\sqrt{3}+2-\sqrt{3}=2+\sqrt{3}\)

b: \(=\sqrt{3}-1+2-\sqrt{3}=1\)

c: \(=2-\sqrt{3}+2-\sqrt{3}=4-2\sqrt{3}\)

\(3\sqrt{25}-\sqrt{36}-2\sqrt{16}=\sqrt{225}-\sqrt{36}-\sqrt{64}=15-6-8=1\)

`3\sqrt{25}-\sqrt{36}-2\sqrt{16}`

`=3\sqrt{5^2}-\sqrt{6^2}-2\sqrt{4^2}`

`=3.5-6-2.4=15-6-8=1`

\(\left(3+\sqrt{2}\right)^2-11=9+6\sqrt{2}+4-11=2+6\sqrt{2}\)

`(3 + sqrt 2 + sqrt 11) (3+ sqrt 2 - sqrt 11)`

`= 3 + sqrt 2 - 11`

`= -9 + sqrt 2`.

l al = 1,5 => a = 1,5 hoặc a = -1,5 

(+) a = 1,5 

M = 1,5 + 2.1,5.-0,75 - - 0,75 = 1,5 + 3.-0,75 + 0,75 = 0 

N , P tính tương tự 

(+) a = -1,5 ; b = -0,75 thay vào ta có

M = ....

Tự làm  tiếp nha

a) Ta có: \(A=\left(\dfrac{2\sqrt{x}}{\sqrt{x}+3}-\dfrac{\sqrt{x}}{3-\sqrt{x}}-\dfrac{3x+3}{x-9}\right):\dfrac{\sqrt{x}+1}{\sqrt{x}-3}\)

\(=\dfrac{2x-6\sqrt{x}+x+3\sqrt{x}-3x-3}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}\cdot\dfrac{\sqrt{x}-3}{\sqrt{x}+1}\)

\(=\dfrac{-3\sqrt{x}-3}{\sqrt{x}+3}\cdot\dfrac{1}{\sqrt{x}+1}\)

\(=\dfrac{-3}{\sqrt{x}+3}\)

b) Ta có: \(x=\sqrt{3+2\sqrt{2}}-\sqrt{3-2\sqrt{2}}\)

\(=\sqrt{2}+1-\sqrt{2}+1\)

=2

Thay x=2 vào A, ta được:

\(A=\dfrac{-3}{3+\sqrt{2}}=\dfrac{-9+3\sqrt{2}}{7}\)

`\sqrt{(3-\sqrt{5})^2}+\sqrt{5}=|3-\sqrt{5}|+\sqrt{5}=3-\sqrt{5}+\sqrt{5}=3`

`\sqrt{3}-\sqrt{(1+\sqrt{3})^2}=\sqrt{3}-|1+\sqrt{3}|=\sqrt{3}-1-\sqrt{3}=-1`

`\sqrt{(\sqrt{3}-1)^2}-\sqrt{3}=|\sqrt{3}-1|-\sqrt{3}=\sqrt{3}-1-\sqrt{3}=-1`

\(\sqrt{\left(3-\sqrt{5}\right)^2}+\sqrt{5}=\left|3-\sqrt{5}\right|+\sqrt{5}=3-\sqrt{5}+\sqrt{5}=3\)

\(\sqrt{3}-\sqrt{\left(1+\sqrt{3}\right)^2}=\sqrt{3}-\left|1+\sqrt{3}\right|=\sqrt{3}-1-\sqrt{3}=-1\)

\(\sqrt{\left(\sqrt{3}-1\right)^2}-\sqrt{3}=\left|\sqrt{3}-1\right|-\sqrt{3}=\sqrt{3}-1-\sqrt{3}=-1\)

kết bạn nha

\(\frac{\left(2+\sqrt{3}\right)\left(\sqrt{2-\sqrt{3}}\right)}{\sqrt{2+\sqrt{3}}}=\frac{\left(\sqrt{2+\sqrt{3}}\right)^2\left(\sqrt{2-\sqrt{3}}\right)}{\sqrt{2+\sqrt{3}}}\)

\(=\frac{\sqrt{2+\sqrt{3}}\cdot\sqrt{2+\sqrt{3}}\cdot\sqrt{2-\sqrt{3}}}{\sqrt{2+\sqrt{3}}}=\sqrt{\left(2+\sqrt{3}\right)\left(2-\sqrt{3}\right)}\)

\(=\sqrt{4-3}=1\)

1: ĐKXĐ: \(a\ge0\)