Giai pt: \(\sqrt{x+1+\sqrt{x+\frac{3}{4}}}+x=-\frac{1}{4}\)
1. Cho pt: x2 -2(m+1)x+m2=0 (1). Tìm m để pt có 2 nghiệm x1 ; x2 thỏa mãn (x1-m)2 + x2=m+2.
2. Giai pt: \(\left(x-1\right)\sqrt{2\left(x^2+4\right)}=x^2-x-2\)
3. Giai hệ pt: \(\left\{{}\begin{matrix}\frac{1}{\sqrt[]{x}}-\frac{\sqrt{x}}{y}=x^2+xy-2y^2\left(1\right)\\\left(\sqrt{x+3}-\sqrt{y}\right)\left(1+\sqrt{x^2+3x}\right)=3\left(2\right)\end{matrix}\right.\)
4. Giai pt trên tập số nguyên \(x^{2015}=\sqrt{y\left(y+1\right)\left(y+2\right)\left(y+3\right)}+1\)
giai pt:
a) \(\frac{3x+\sqrt{x^2-x-1}}{x+1}=\frac{7}{3}\)
b) \(\frac{2}{2\sqrt{x^2-2x+1}}=\frac{1}{x-1}\)
c) \(\frac{6}{6-\sqrt{x}}+\frac{1}{\sqrt{x}}=1\)
d) \(\frac{2}{\sqrt{x-1}}+\sqrt{x-1}=\frac{3\sqrt{x-1}+1}{\sqrt{x-1}}-1\)
e) \(\sqrt{x+3-\sqrt{x-1}=2}\)
f) \(\sqrt{x^3+x^2+6x+28}=x+5\)
g) \(\sqrt{x^4-4x^3+14x-11}=1-x\)
ĐK: \(x^4-4x^3+14x-11\ge0\) (*)
\(PT\Leftrightarrow\left\{{}\begin{matrix}x\le1\\x^4-4x^3+14x-11=x^2-2x+1\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\le1\\x^4-4x^3-x^2+16x-12=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\le1\\\left(x-1\right)\left(x-2\right)\left(x-3\right)\left(x+2\right)=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)(tm)
e/ ĐKXĐ: \(x\ge1\)
\(\Leftrightarrow x+3-\sqrt{x-1}=4\)
\(\Leftrightarrow\sqrt{x-1}=x-1\)
\(\Leftrightarrow x-1=x^2-2x+1\)
\(\Leftrightarrow x^2-3x+2=0\Rightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\)
f/ \(\Leftrightarrow\left\{{}\begin{matrix}x+5\ge0\\x^3+x^2+6x+28=\left(x+5\right)^2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-5\\x^3-4x+3=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge-5\\\left(x-1\right)\left(x^2+x-3\right)=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=1\\x=\frac{-1\pm\sqrt{13}}{2}\\\end{matrix}\right.\)
a/ ĐKXĐ: ...
\(\Leftrightarrow9x+3\sqrt{x^2-x-1}=7x+7\)
\(\Leftrightarrow3\sqrt{x^2-x-1}=7-2x\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\le\frac{7}{2}\\9\left(x^2-x-1\right)=\left(7-2x\right)^2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\le\frac{7}{2}\\5x^2+19x-58=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=2\\x=-\frac{29}{5}\end{matrix}\right.\)
b/ ĐKXĐ: \(x\ne1\)
\(\Leftrightarrow\frac{1}{\sqrt{\left(x-1\right)^2}}=\frac{1}{x-1}\)
\(\Leftrightarrow\frac{1}{\left|x-1\right|}=\frac{1}{x-1}\)
\(\Rightarrow x-1>0\Rightarrow x>1\)
Giai pt\(2+\sqrt{4-3\sqrt{10-x}}=\frac{x}{3}\)
Giai PT \(\sqrt{x-\frac{1}{x}}-\sqrt{1-\frac{1}{x}}=\frac{x-1}{x}\)
a) Giải PT \(x=\sqrt{x}+6\)
b) Giai PT \(\frac{x+1}{x-2}+\frac{3-x}{x}=4\)
Giai pt \(a,4\sqrt{x+1}=x^2+5x+4\)
\(b,\sqrt{4x+1}-\sqrt{3x-2}=\frac{x+3}{5}\)
\(c,2x^2-5x+5=\sqrt{5x-1}\)
a/ Dặt \(\sqrt{x+1}=a\ge0\)
\(\Rightarrow4\sqrt{x+1}=x^2+5x+4\)
\(\Leftrightarrow4\sqrt{x+1}=\left(x+1\right)^2+3\left(x+1\right)\)
\(\Leftrightarrow4a=a^4+3a^2\)
\(\Leftrightarrow a\left(a-1\right)\left(a^2+a+4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}a=0\\a=1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}\sqrt{x+1}=0\\\sqrt{x+1}=1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=-1\\x=0\end{cases}}\)
b/ Đặt \(\hept{\begin{cases}\sqrt{4x+1}=a\ge0\\\sqrt{3x-2}=b\ge0\end{cases}}\)
\(\Rightarrow a^2-b^2=x+3\)
Từ đây ta có:
\(a-b=\frac{a^2-b^2}{5}\)
\(\Leftrightarrow\left(a-b\right)\left(5-a-b\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}a=b\left(1\right)\\a+b=5\left(2\right)\end{cases}}\)
Thế vô làm tiếp
c/
\(2x^2-5x+5=\sqrt{5x-1}\)
\(\Leftrightarrow\left(2x^2-5x+5\right)^2=5x-1\)
\(\Leftrightarrow4x^4-20x^3+45x^2-55x+26=0\)
\(\Leftrightarrow\left(x^2-3x+2\right)\left(4x^2-8x+13\right)=0\)
Làm nốt
a. Tìm x thoả man đk \(\sqrt{\frac{4x+3}{x+1}}=3\)
b. Giải pt: \(\frac{1}{\sqrt{x+5}+\sqrt{x+4}}+\frac{1}{\sqrt{x+4}+\sqrt{x+3}}+\frac{1}{\sqrt{x+3}+\sqrt{x+2}}+\frac{1}{\sqrt{x+2}+\sqrt{x+1}}+\frac{1}{\sqrt{x+1}+\sqrt{x}}=1\)
c. Tìm các cặp số nguyên dương(x,y) thoả mãn: \(6x+5y+18=2xy\)
a/ ĐKXĐ: ...
\(\Leftrightarrow\frac{4x+3}{x+1}=9\Leftrightarrow4x+3=9\left(x+1\right)\)
\(\Leftrightarrow5x=-6\Rightarrow x=-\frac{6}{5}\)
b/ ĐKXĐ: \(x\ge0\)
Nhân cả tử và mẫu của từng số hạng với biểu thức liên hợp và rút gọn ra được:
\(\sqrt{x+5}-\sqrt{x+4}+\sqrt{x+4}-\sqrt{x+3}+...+\sqrt{x+1}-\sqrt{x}=1\)
\(\Leftrightarrow\sqrt{x+5}-\sqrt{x}=1\)
\(\Leftrightarrow\sqrt{x+5}=1+\sqrt{x}\)
\(\Leftrightarrow x+5=x+1+2\sqrt{x}\)
\(\Leftrightarrow\sqrt{x}=2\Rightarrow x=4\)
c/ \(\Leftrightarrow2xy-6x-5y+15=33\)
\(\Leftrightarrow2x\left(y-3\right)-5\left(y-3\right)=33\)
\(\Leftrightarrow\left(2x-5\right)\left(y-3\right)=33\)
Đến đây là pt ước số đơn giản rồi
Nghiệm nhỏ nhất của pt\(\frac{1}{2\sqrt{x}-2014}+\frac{1}{3\sqrt{x}+2013}=\frac{1}{2015-4\sqrt{x}}+\frac{1}{9\sqrt{x}-2016}\)
Giai phương trình:
(\(\frac{x+2}{x\sqrt{x}+1}-\frac{1}{\sqrt{x}+1}\))\(\cdot\frac{4\sqrt{x}}{3}\)