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LV
Giải phương trình: a) 3x+2=6x-7 b) 2 1 3x-11 ------- - ----- = ------------------ x+1 x-2 (x+1)(x-2)
2
13 tháng 5 2023
\(a,3x+2=6x-7\)
\(\Leftrightarrow3x-6x=-7-2\)
\(\Leftrightarrow-3x=-9\)
\(\Leftrightarrow x=3\)
Câu còn lại mình ko rõ đề bài bạn ơi^^
LH
2
13 tháng 8 2021
1/ ( x-3) 2=16
\(\Rightarrow\left[{}\begin{matrix}x-3=4\\x-3=-4\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=7\\x=-1\end{matrix}\right.\)
2/ (3x-1)3=8
\(\Rightarrow3x-1=2\\ \Rightarrow3x=3\\ \Rightarrow x=1\)
3/ (x-11)3=-27
\(\Rightarrow x-11=-3\\ \Rightarrow x=8\)
phần 4 mình ko rõ đề
LN
2
24 tháng 1 2022
\(ĐKXĐ:\left\{{}\begin{matrix}x\ne-1\\x\ne2\end{matrix}\right.\)
\(\dfrac{2}{x+1}-\dfrac{1}{x-2}=\dfrac{3x-11}{\left(x+1\right)\left(x-2\right)}\\ \Leftrightarrow\dfrac{2\left(x-2\right)}{\left(x+1\right)\left(x-2\right)}-\dfrac{x+1}{\left(x+1\right)\left(x-2\right)}=\dfrac{3x-11}{\left(x+1\right)\left(x-2\right)}\\ \Leftrightarrow2\left(x-2\right)-\left(x+1\right)=3x-11\\ \Leftrightarrow2x-4-x-1-3x+11=0\\ \Leftrightarrow-2x+6=0\\ \Leftrightarrow-2x=-6\\ \Leftrightarrow x=3\left(tm\right)\)
LD
24 tháng 1 2022
\(\Leftrightarrow\dfrac{2\left(x-2\right)-\left(x+1\right)}{\left(x+1\right)\left(x-2\right)}=\dfrac{3x-11}{\left(x+1\right)\left(x-2\right)}\)
\(\Leftrightarrow2x-4-x-1=3x-11\left(khử\cdot mẫu\right)\)
\(\Leftrightarrow2x-x-3x=-11+4+1\)
\(\Leftrightarrow-2x=-6\)
\(\Leftrightarrow x=3\)
Vậy \(S=\left\{3\right\}\)
16 tháng 5 2023
\(\dfrac{2}{x+1}-\dfrac{1}{x-2}=\dfrac{3x-11}{\left(x+1\right)\left(x-2\right)}\\ ĐKXĐ:x\ne-1;x\ne2\\ \dfrac{2}{x+1}-\dfrac{1}{x-2}=\dfrac{3x-11}{\left(x+1\right)\left(x-2\right)}\\ \Leftrightarrow\dfrac{2\left(x-2\right)}{\left(x+1\right)\left(x-2\right)}-\dfrac{1\left(x+1\right)}{\left(x-2\right)\left(x+1\right)}=\dfrac{3x-11}{\left(x+1\right)\left(x-2\right)}\\ \Rightarrow2x-4-x-1=3x-11\\ \Leftrightarrow2x-x-3x=-11+4+1\\ \Leftrightarrow-2x=-6\\ \Leftrightarrow x=3\left(tm\right)\)
Vậy \(S=\left\{3\right\}\)
F
0
22 tháng 1 2022
\(x\ne-1,x\ne2\\ \Leftrightarrow2x-4-x-1=3x-11\\ 6=2x\\ x=6:2=3_{\left(tmđk\right)}\)
24 tháng 4 2022
1.a)|−7x|=3x+16
Vì |-7x| ≥ 0 nên 3x+16 ≥ 0 ⇔ x ≥ \(\dfrac{-16}{3}\) (*)
Với đk (*), ta có: |-7x|=3x+16
\(\left[\begin{array}{} -7x=3x+16\\ -7x=-3x-16 \end{array} \right.\) ⇔ \(\left[\begin{array}{} -7x-3x=16\\ -7x+3x=-16 \end{array} \right.\)
⇔ \(\left[\begin{array}{} x=-1,6 (t/m)\\ x= 4 (t/m) \end{array} \right.\)
b) \(\dfrac{x-1}{x+2}\) - \(\dfrac{x}{x-2}\) = \(\dfrac{5x-8}{x^2-4}\)
⇔ \(\dfrac{(x-1)(x-2)}{x^2-4}\) - \(\dfrac{x(x+2)}{x^2-4}\) = \(\dfrac{5x-8}{x^2-4}\)
⇒ x2 - 2x - x + 2 - x2 - 2x = 5x - 8
⇔ -5x - 5x = -8 - 2
⇔ -10x = -10
⇔ x=1
2.7x+5 < 3x−11
⇔ 7x - 3x < -11 - 5
⇔ 4x < -16
⇔ x < -4
bạn tự biểu diễn trên trục số nha !
VD
21 tháng 3 2022
\(a,\left(2x-3\right)\left(x^2-4\right)=0\\ \Leftrightarrow\left(2x-3\right)\left(x-2\right)\left(x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=2\\x=-2\end{matrix}\right.\\ b,2x-\left(3-5x\right)=4\left(x+3\right)\\ \Leftrightarrow2x-3+5x=4x+12\\ \Leftrightarrow7x-3-4x-12=0\\ \Leftrightarrow3x-15=0\\ \Leftrightarrow x=5\)
\(c,ĐKXĐ:\left\{{}\begin{matrix}x\ne-1\\x\ne2\end{matrix}\right.\)
\(\dfrac{1}{x-2}-\dfrac{2}{x+1}=\dfrac{11-3x}{\left(x+1\right)\left(x-2\right)}\\ \Leftrightarrow\dfrac{x+1}{\left(x-2\right)\left(x+1\right)}-\dfrac{x-2}{\left(x+1\right)\left(x-2\right)}-\dfrac{11-3x}{\left(x+1\right)\left(x-2\right)}=0\\ \Leftrightarrow\dfrac{x+1-x+2-11+3x}{\left(x+1\right)\left(x-2\right)}=0\\ \Rightarrow3x-8=0\\ \Leftrightarrow x=\dfrac{8}{3}\left(tm\right)\)
5 tháng 2 2022
e) ĐK : \(\left\{{}\begin{matrix}1+3x\ne0\\1-3x\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3x\ne-1\\3x\ne1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ne\dfrac{-1}{3}\\x\ne\dfrac{1}{3}\end{matrix}\right.\)
\(\Leftrightarrow\dfrac{12}{\left(1-3x\right)\left(1+3x\right)}=\dfrac{\left(1-3x\right)^2-\left(1+3x\right)^2}{\left(1+3x\right)\left(1-3x\right)}\)
\(\Leftrightarrow12\left(1+3x\right)\left(1-3x\right)=\left(1-3x\right)\left(1+3x\right)\left(1-3x-1-3x\right)\left(1-3x+1+3x\right)\)
\(\Leftrightarrow12=\left(-6x\right).2\Leftrightarrow6=-6x\)
\(\Leftrightarrow x=-1\left(TM\right)\)
\(\frac{2}{x+1}-\frac{1}{x-2}=\frac{3x-11}{\left(x+1\right)\left(x-2\right)}\)
\(\Leftrightarrow2\left(x-2\right)-\left(x+1\right)=3x-11\)
\(\Leftrightarrow2x-4-x-1=3x-11\)
\(\Leftrightarrow x-5=3x-11\)
\(\Leftrightarrow x-3x=5-11\)
\(\Leftrightarrow-2x=-6\)
\(\Leftrightarrow x=3\)