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a: \(3x-12-4\sqrt{x}+8=6\sqrt{2x+1}-18\)
=>\(\left(x-4\right)\cdot3-4\left(\sqrt{x}-2\right)=6\left(\sqrt{2x+1}-3\right)\)
=>\(3\left(x-4\right)-\dfrac{4\left(x-4\right)}{\sqrt{x}+2}-6\cdot\dfrac{2x+1-9}{\sqrt{2x+1}+3}=0\)
=>\(\left(x-4\right)\left(3-\dfrac{4}{\sqrt{x}+2}-\dfrac{12}{\sqrt{2x+1}+3}\right)=0\)
=>x-4=0
=>x=4
b: \(\Leftrightarrow\sqrt{x^2+x-1}-1+\sqrt{x-x^2+1}-1=x^2-x\)
=>\(\dfrac{x^2+x-1-1}{\sqrt{x^2+x-1}+1}+\dfrac{x-x^2+1-1}{\sqrt{x-x^2+1}+1}=x\left(x-1\right)\)
=>\(\dfrac{\left(x+2\right)\left(x-1\right)}{\sqrt{x^2+x-1}+1}-\dfrac{x\left(x-1\right)}{\sqrt{x-x^2+1}+1}-x\left(x-1\right)=0\)
=>\(\left(x-1\right)\left(\dfrac{x+2}{\sqrt{x^2+x-1}+1}-\dfrac{x}{\sqrt{x-x^2+1}+1}-x\right)=0\)
=>x-1=0
=>x=1
c: \(\Leftrightarrow x^2-\sqrt{x^3-x^2}-\sqrt{x^2-x}=0\)
=>\(\sqrt{x}\left(x\sqrt{x}-\sqrt{x^2-x}-\sqrt{x-1}\right)=0\)
=>căn x=0
=>x=0
`(4\sqrt{6}+x)^2=8^2+(6+\sqrt{x^2+4})^2`
`<=>96+8\sqrt{6}x+x^2=64+36+12\sqrt{x^2+4}+x^2+4`
`<=>2\sqrt{6}x-2=3\sqrt{x^2+4}` `ĐK: x >= \sqrt{6}/6`
`<=>24x^2-8\sqrt{6}x+4=9x^2+36`
`<=>15x^2-8\sqrt{6}x-32=0`
`<=>x^2-[8\sqrt{6}]/15x-32/15=0`
`<=>(x-[4\sqrt{6}]/15)^2-64/25=0`
`<=>|x-[4\sqrt{6}]/15|=8/5`
`<=>[(x=[24+4\sqrt{6}]/15 (t//m)),(x=[-24+4\sqrt{6}]/15(ko t//m)):}`
Bài 1:
a: \(=\left(\sqrt{5}+\sqrt{3}\right)\left(\sqrt{5}-\sqrt{3}\right)=2\)
b: \(=\sqrt{11}+\sqrt{2}-\sqrt{11}-\sqrt{7}-\sqrt{2}=-\sqrt{7}\)
\(=\dfrac{\sqrt{x}+1}{\sqrt{x}\left(\sqrt{x}-1\right)}\cdot\dfrac{\left(\sqrt{x}-1\right)^2}{\sqrt{x}+1}=\dfrac{\sqrt{x}-1}{\sqrt{x}}\)