Giải phương trình sau:
X - 3/2 + X - 5/6 = -1/3
Giúp mình nhé!!!
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Tôi nghĩ là như này :)) Sai thì chịu nhá :((
Ta có pt : \(\left|x+1\right|+3\left|x-1\right|=x+2+\left|x\right|+2\left|x-2\right|\) (1)
Ta thấy VT pt (1) là : \(\left|x+1\right|+3\left|x-1\right|\ge0\forall x\)
Nên VP pt (1) cũng phải lớn hơn bằng 0
Có nghĩa là \(x+2\ge0\) \(\Leftrightarrow x\ge-2\)
Khi đó : \(\left\{{}\begin{matrix}\left|x+1\right|=-\left(x+1\right)\\3\left|x-1\right|=3\left(1-x\right)\\\left|x\right|=-x\\2\left|x-2\right|=2\left(2-x\right)\end{matrix}\right.\)
Vậy pt (1) \(\Leftrightarrow-x-1+3-3x=x+2-x+4-2x\)
\(\Leftrightarrow2x=-4\Leftrightarrow x=-2\) ( thỏa mãn )
Vậy \(x=-2\) thỏa mãn pt.
\(\left|x+1\right|\) | - | + | + | + | + |
3\(\left|x-1\right|\) | - | - | + | + | + |
\(\left|x\right|\) | - | - | - | + | + |
\(2\left|x-2\right|\) | - | - | - | - | + |
PT | 2x-4=5x-2 | 2x-4=5x-2 | -4x+2=2x-2 | -4x+2=-2x+6 |
-1 0 1 2
1) x=-2/3>-1( loại)
2)
Nhận thấy \(x=0\) không phải nghiệm, chia 2 vế cho \(x^2\)
\(6x^2+7x-36+\frac{7}{x}+\frac{6}{x^2}=0\)
\(\Leftrightarrow6\left(x^2+\frac{1}{x^2}\right)+7\left(x+\frac{1}{x}\right)-36=0\)
Đặt \(x+\frac{1}{x}=a\) (\(\left|a\right|\ge2\)) \(\Rightarrow x^2+\frac{1}{x^2}=a^2-2\)
\(6\left(a^2-2\right)+7a-36=0\)
\(\Leftrightarrow6a^2+7a-48=0\)
Nghiệm xấu
Ta có : x2-2x+3|x-1| < 3
\(\left(x-1\right)^3+\left(2x-1\right)^3=\left(3x-2\right)^3\)
\(\left(3x-2\right)\left[\left(x-1\right)^2-\left(x-1\right)\left(2x-1\right)+\left(2x-1\right)^2-\left(3x-2\right)^2\right]=0\)
\(\left(3x-2\right).\left(-3\right)\left(2x^2-3x+1\right)=0\)
\(\left(3x-2\right)\left(x-1\right)\left(2x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=1\\x=\frac{1}{2}\\x=\frac{2}{3}\end{matrix}\right.\)
Vậy ....
\(Dk:x,y\ge\frac{-5}{4}\)
\(\left\{{}\begin{matrix}\left(2x-3\right)^2=4y+5\\\left(2y-3\right)^2=4x+5\end{matrix}\right.\Rightarrow\left(2y-3\right)^2-\left(2x-3\right)^2=4x-4y\Leftrightarrow\left(2y-2x\right)\left(2x+2y-6\right)=4\left(x-y\right)\Leftrightarrow4\left(y-x\right)\left(x+y-3\right)=4\left(x-y\right)\Leftrightarrow-4\left(x-y\right)\left(x+y-3\right)=4\left(x-y\right)\)
\(+,x=y\Rightarrow\left(2x-3\right)^2=4x+5\Leftrightarrow4x^2-12x+9=4x+5\Leftrightarrow4x^2-16x+4=0\Leftrightarrow x^2-4x+1=0\)
\(\Delta=16-4=12>0\Rightarrow\left[{}\begin{matrix}x=2+\sqrt{3}\\x=2-\sqrt{3}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=y=2+\sqrt{3}\left(tm\right)\\x=y=2-\sqrt{3}\left(tm\right)\end{matrix}\right.\)
\(+,x\ne y\Rightarrow-4\left(x+y-3\right)=4\Leftrightarrow x+y-3=-1\Leftrightarrow x+y=2\)
\(\Leftrightarrow x=2-y\Rightarrow\left(1-2y\right)^2=4y+5\Leftrightarrow1-4y+4y^2=4y+5\Leftrightarrow4y^2-8y-4=0\Leftrightarrow y^2-2y-1=0;\Delta=\left(-2\right)^2-\left(-1\right).1.4=4-\left(-4\right)=8>0\Rightarrow\left[{}\begin{matrix}x=1+\sqrt{2}\\x=1-\sqrt{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}y=1-\sqrt{2};x=1+\sqrt{2}\left(tm\right)\\x=1-\sqrt{2};y=1+\sqrt{2}\left(tm\right)\end{matrix}\right.\)
\(\left(x-2\right)\left(4x+5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-2=0\\4x+5=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-\frac{5}{4}\end{matrix}\right.\\ \Rightarrow S=\left\{-\frac{5}{4};2\right\}\)
X-\(\frac{3}{2}\)+X-\(\frac{5}{6}\)=\(-\frac{1}{3}\)
➜2X=\(-\frac{1}{3}\)+\(\frac{3}{2}+\frac{5}{6}\)
➜ 2X=2
➜X = 1
Vậy....................
Lộn đề rồi