\(\sqrt{2x+4}=\frac{6x-4}{\sqrt{x^2+4}}+2\sqrt{2-x}\)
Giải pt sau :
1, \(\sqrt{x+1}+\sqrt{4-x}+\sqrt{\left(x+1\right)\left(4-x\right)}=5\)
2, \(\sqrt{x+4}+\sqrt{x-4}=2x-12+2\sqrt{x^2-16}\)
3, \(\sqrt{x+\sqrt{6x-9}}+\sqrt{x-\sqrt{6x-9}}=\sqrt{6}\)
4, \(\frac{4}{x+\sqrt{x^2+x}}-\frac{1}{x-\sqrt{x^2+x}}=\frac{3}{x}\)
5, \(\sqrt{x^2+x+4}+\sqrt{x^2+x+1}=\sqrt{2x^2+2x+9}\)
1.
ĐK: \(-1\le x\le4\)
Đặt \(\sqrt{x+1}+\sqrt{4-x}=t\left(t\ge0\right)\)
\(\Leftrightarrow\sqrt{\left(x+1\right)\left(4-x\right)}=\frac{t^2-5}{2}\)
\(PT\Leftrightarrow t+\frac{t^2-5}{2}=5\Rightarrow t^2+2t-15=0\) \(\Rightarrow\left[{}\begin{matrix}t=3\\t=-5\left(l\right)\end{matrix}\right.\)
\(t=3\Rightarrow\sqrt{-x^2+3x+4}=2\) \(\Leftrightarrow-x^2+3x+4=4\Rightarrow\left[{}\begin{matrix}x=0\\x=3\end{matrix}\right.\) (tm)
2.
ĐK:\(x\ge4\)
Đặt \(\sqrt{x+4}+\sqrt{x-4}=t\left(t\ge0\right)\)
\(\Rightarrow2\sqrt{x^2-16}=t^2-2x\)
\(PT\Leftrightarrow t=2x-12+t^2-2x\)
\(\Leftrightarrow t^2-t-12=0\Rightarrow\left[{}\begin{matrix}t=4\\t=-3\left(l\right)\end{matrix}\right.\) Giải tiếp như trên.
Rút gọn:
\(A=\sqrt{x+\sqrt{x^2-4}}+\sqrt{x-\sqrt{x^2-4}}\)
\(B=\sqrt{10x-6\sqrt{x^2-2x}-2}+\sqrt{5x+4\sqrt{x^2-2x}-2}\)
\(C=\frac{\sqrt{2+\sqrt{-x^2+6x-8}}}{x-3}\)
\(D=\sqrt{\frac{17}{4}+2\sqrt{4-x^2}+\sqrt{4+2\sqrt{4-x^2}}}\)
Giúp mình với các bạn
Giải phương trình: \(\sqrt{2x+4}=\frac{6x-4}{\sqrt{x^2+4}}+2\sqrt{2-x}\)
Bn tham khảo nhé.
Link nè:
$\sqrt{2x+4}-2\sqrt{2-x}=\frac{6x-4}{\sqrt{x^{2}+4}}$ - Phương trình - hệ phương trình - bất phương trình - Diễn đàn Toán học
tìm điều kiện xác định của biểu thức:
\(a)\frac{6x}{-\sqrt{x+7}}-\frac{3}{-5x-4}+\frac{\sqrt{x}}{-3x+2}\)
\(b)\frac{5-\sqrt{x}}{x+4}+\frac{\sqrt{x-2}-3}{-2x-10}\)
\(c)\frac{\sqrt{6x}}{-x-3}-\frac{4x}{2x+3}\)
\(d)\frac{\sqrt{2x-7}}{3x-4}-\frac{\sqrt{6x}}{x-3}+3x-1\)
a) \(\left\{{}\begin{matrix}x\ge0\\-\sqrt{x+7}< 0\\-5x-4\ne0\\-3x+2\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x+7>0\\-5x\ne4\\-3x\ne-2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x>-7\\x\ne\frac{-4}{5}\\x\ne\frac{2}{3}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x\ne\frac{2}{3}\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}x\ge0\\x+4\ne0\\x-2\ge0\\-2x-10\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x\ne-4\\x\ge2\\-2x\ne10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\x\ne-5\end{matrix}\right.\Leftrightarrow x\ge2\)
c) \(\left\{{}\begin{matrix}x\ge0\\-x-3\ne0\\2x+3\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x\ne-3\\x\ne-\frac{3}{2}\end{matrix}\right.\Leftrightarrow x\ge0\)
d) \(\left\{{}\begin{matrix}2x-7\ge0\\x\ge0\\3x-4\ne0\\x-3\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge\frac{7}{2}\\x\ge0\\x\ne\frac{4}{3}\\x\ne3\end{matrix}\right.\Leftrightarrow x\ge\frac{7}{2}\)
1. giải các phương trình :
a/\(\sqrt{6x^2-12x+7}=x^2-2x\)
\(\frac{2}{\sqrt{3+x}}=\frac{\sqrt{3+x}}{x-1}\)
c/\(x^2+\sqrt{-x-1}=4+\sqrt{-x-1}\)
d/\(\frac{3x^2+1}{\sqrt{x-1}}=\frac{4}{\sqrt{x-1}}\)
e/\(\sqrt{-x^2+3x+4}=2x^2-6x+2\)
f/\(\frac{\sqrt{4x^2+7x-2}}{x+2}=\sqrt{2}\)
a, ĐK: \(6x^2-12x+7\ge0\) (*)
\(PT\Leftrightarrow\left\{{}\begin{matrix}x^2-2x\ge0\\6x^2-12x+7=x^4-4x^3+4x^2\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x^2-2x\ge0\\x^4-4x^3-2x^2+12x-7=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x^2-2x\ge0\\\left(x-1\right)^2\left(x^2-2x-7\right)=0\end{matrix}\right.\) \(\Rightarrow x=1\pm2\sqrt{2}\) (thỏa mãn ĐK)
Vậy...
giải pt sau:
a, \(\sqrt{2x+4}-2\sqrt{2-x}=\frac{6x-4}{\sqrt{x^2}+4}\)
Giải phương trình vô tỉ :
\(\sqrt{2x+4}-2\sqrt{2-x}=\frac{6x-4}{\sqrt{x^2+4}}\)
Giải phương trình vô tỉ :
a) \(\left(\sqrt{x+3}-\sqrt{x-1}\right)\left(x^2+\sqrt{x^2+4x+3}\right)=2x\)
b) \(\sqrt{2x+4}-2\sqrt{2-x}=\frac{6x-4}{\sqrt{x^2+4}}\)
c) \(\sqrt{3x^2-4x+2}+\sqrt{3x+1}+\sqrt{2x-1}+6x^3-7x^2-3=0\)
d) \(\sqrt{x^2+15}=3x-2+\sqrt{x^2+8}\)
giải pt
a) \(\sqrt{2x^2+5x+2}-2\sqrt{2x^2+5x-6}=0\)
b) \(\sqrt[5]{\frac{16x}{x-1}}+\sqrt[5]{\frac{x-1}{16x}}=\frac{5}{2}\)
c) \(\sqrt{6x^2-12x+7}+2x=x^2\)
d) \(x\left(x+1\right)-\sqrt{x^2+x+4}+2=0\)
e) \(\sqrt{3x^2+6x+4}=2-2x-x^2\)
a/ ĐKXĐ: ...
\(\Leftrightarrow\sqrt{2x^2+5x+2}=2\sqrt{2x^2+5x-6}\)
\(\Leftrightarrow2x^2+5x+2=4\left(2x^2+5x-6\right)\)
\(\Leftrightarrow6x^2+15x-26=0\)
b/ ĐKXĐ: ...
Đặt \(\sqrt[5]{\frac{16x}{x-1}}=a\)
\(a+\frac{1}{a}=\frac{5}{2}\Leftrightarrow a^2-\frac{5}{2}a+1=0\)
\(\Rightarrow\left[{}\begin{matrix}a=2\\a=\frac{1}{2}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\sqrt[5]{\frac{16x}{x-1}}=2\\\sqrt[5]{\frac{16x}{x-1}}=\frac{1}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}16x=32\left(x-1\right)\\16x=\frac{1}{32}\left(x-1\right)\end{matrix}\right.\)
c/ĐKXĐ: ...
\(\Leftrightarrow x^2-2x-\sqrt{6x^2-12x+7}=0\)
Đặt \(\sqrt{6x^2-12x+7}=a\ge0\Rightarrow x^2-2x=\frac{a^2-7}{6}\)
\(\frac{a^2-7}{6}-a=0\Leftrightarrow a^2-6a-7=0\)
\(\Rightarrow\left[{}\begin{matrix}a=-1\left(l\right)\\a=7\end{matrix}\right.\) \(\Rightarrow\sqrt{6x^2-12x+7}=7\)
\(\Leftrightarrow6x^2-12x-42=0\)
d/ \(\Leftrightarrow x^2+x+4-\sqrt{x^2+x+4}-2=0\)
Đặt \(\sqrt{x^2+x+4}=a>0\)
\(a^2-a-2=0\Rightarrow\left[{}\begin{matrix}a=-1\left(l\right)\\a=2\end{matrix}\right.\)
\(\Rightarrow\sqrt{x^2+x+4}=2\Rightarrow x^2+x=0\)
e/ \(\Leftrightarrow x^2+2x+\sqrt{3x^2+6x+4}-2=0\)
Đặt \(\sqrt{3x^2+6x+4}=a>0\Rightarrow x^2+2x=\frac{a^2-4}{3}\)
\(\frac{a^2-4}{3}+a-2=0\)
\(\Leftrightarrow a^2+3a-10=0\Rightarrow\left[{}\begin{matrix}a=2\\a=-5\left(l\right)\end{matrix}\right.\)
\(\Rightarrow\sqrt{3x^2+6x+4}=2\Rightarrow3x^2+6x=0\)
ĐKXĐ:...
a/ \(\sqrt{2x^2+5x+2}=1+2\sqrt{2x^2+5x-6}\)
\(\Leftrightarrow2x^2+5x+2=4\left(2x^2+5x-6\right)+1+4\sqrt{2x^2+5x-6}\)
\(\Leftrightarrow3\left(2x^2+6x-6\right)+4\sqrt{2x^2+5x-6}-7=0\)
Đặt \(\sqrt{2x^2+5x-6}=a\ge0\)
\(3a^2+4a-7=0\Rightarrow\left[{}\begin{matrix}a=1\\a=-\frac{7}{3}\left(l\right)\end{matrix}\right.\)
\(\Rightarrow\sqrt{2x^2+5x-6}=1\)
\(\Leftrightarrow2x^2+5x-7=0\)