Giải các phương trình:
a) x − 2 = 3 ; b) 3 + x = − 2 ;
c) 5 − x = 2 x − 3 ; d) x − 1 2 = 3 2 + x
giải các phương trình:
a)(x2+3x)(x2+3x+4)=-4
b)x(x+1)(x+2)(x+3)=24
Ta có (\(^{x^{2^{ }}^{ }+3x}\)) (\(^{x^{2^{ }}+3x+4}\))
Đặt \(x^{2^{ }^{ }}+3x\) là a ta có
a.(a+4)=-4
4a+\(a^2\) -4=0
\(^{ }\left(a-2\right)^2\)=0
Suy ra a=2
hay \(x^{2^{ }^{ }^{ }}+3x=2\)
\(x^2+3x-2=0\)
𝑥=−3±17√/2
Giải các phương trình:
a) \(\sqrt[3]{x+1}=-5\)
b) \(\sqrt[3]{x+1}-1=x\)
a: Ta có: \(\sqrt[3]{x+1}=-5\)
\(\Leftrightarrow x+1=-125\)
hay x=-126
b: Ta có: \(\sqrt[3]{x+1}-1=x\)
\(\Leftrightarrow x+1=\left(x+1\right)^3\)
\(\Leftrightarrow\left(x+1\right)\left[\left(x+1\right)^2-1\right]=0\)
\(\Leftrightarrow x\left(x+1\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\\x=-2\end{matrix}\right.\)
Giải phương trình:
a.2x+x-3=5
b.3(2-x)-(x+2)=0
a: =>3x=8
hay x=8/3
b: =>6-3x-x-2=0
=>-4x+4=0
hay x=1
\(a,2x+x-3=5\\ \Rightarrow3x=5+3\\ \Rightarrow3x=8\\ \Rightarrow x=\dfrac{8}{3}\\ b,3\left(2-x\right)-\left(x+2\right)=0\\ \Rightarrow6-3x-x-2=0\\ \Rightarrow4-4x=0\\ \Rightarrow4x=4\\ \Rightarrow x=1\)
a,2x+x-3=5
3x-3=5
=>x=\(\dfrac{8}{3}\)
b.3(2-x)-(x+2)=0
6-3x-x-2=0
4-4x=0
=>x=1
Giải phương trình:
a, x^2+3|x|-4=0
b,|x^2-4|=x^2-4
c,(x+1)^2-|3-2x|-|x-2|^2+6=0
d,x^2+4x+3+|2x+5|-(x+1)(x+3) - 5+2x=0
Giải bất phương trình:
a, 2|x-1| <x+1
b, |x-3| > x+1 phần 2
mình đang cần gấp ;-;
1:
a: =>(|x|+4)(|x|-1)=0
=>|x|-1=0
=>x=1; x=-1
b: =>x^2-4>=0
=>x>=2 hoặc x<=-2
d: =>|2x+5|=2x-5
=>x>=5/2 và (2x+5-2x+5)(2x+5+2x-5)=0
=>x=0(loại)
giải các phương trình:
a)(x2+x+1)2-2x2-2x=5
b)\(\dfrac{1}{\left(x-1\right)\left(x-3\right)}\)+x2-4x+5=0
Giải các bất phương trình:
a,\(\frac{x+1}{X-1}\)>0
b,\(\frac{x^2+x-2}{x-9}\)<0
a.
\(\dfrac{x+1}{x-1}>0\Rightarrow\left[{}\begin{matrix}x>1\\x< -1\end{matrix}\right.\)
b.
\(\Leftrightarrow\dfrac{\left(x-1\right)\left(x+2\right)}{x-9}< 0\Rightarrow\left[{}\begin{matrix}x< -2\\1< x< 9\end{matrix}\right.\)
Giải phương trình:
a, \(\dfrac{t}{2a}-\dfrac{4a}{3}=1\)
b, \(\dfrac{x-2a}{b}=2+\dfrac{x+b}{a}\) (a, b là các hằng số)
giải phương trình:
a) 2x/x-1 + 4/x^2+2x-3 = 2x-5/x+3
\(\dfrac{2x}{x-1}+\dfrac{4}{x^2+2x-3}=\dfrac{2x-5}{x+3}\)
\(\Leftrightarrow\dfrac{2x}{x-1}+\dfrac{4}{\left(x-1\right)\left(x+3\right)}=\dfrac{2x-5}{x+3}\)
\(ĐK:x\ne1;-3\)
\(\Leftrightarrow\dfrac{2x\left(x+3\right)+4}{\left(x-1\right)\left(x+3\right)}=\dfrac{\left(2x-5\right)\left(x-1\right)}{\left(x-1\right)\left(x+3\right)}\)
\(\Leftrightarrow2x\left(x+3\right)+4=\left(2x-5\right)\left(x-1\right)\)
\(\Leftrightarrow2x^2+6x+4=2x^2-2x-5x+5\)
\(\Leftrightarrow13x=1\)
\(\Leftrightarrow x=\dfrac{1}{13}\left(tm\right)\)
Giải phương trình:
a/ x2 - 2(x-2) = 4
b/ x2 - 9 - 2x(x - 3) = 0
a/
\(\Leftrightarrow x^2-2x+4-4=0\\ \Leftrightarrow x\left(x-2\right)=0\)
\(\Leftrightarrow x=0;x-2=0\)
\(\Leftrightarrow x=0;x=2\)
b/
\(\Leftrightarrow\left(x-3\right)\left(x+3\right)-2x\left(x-3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+3-2x\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(3-x\right)=0\)
\(\Rightarrow x=3\)
\(a,x^2-2.\left(x-2\right)=4\\ \Leftrightarrow x^2-2x+4-4=0\\ \Leftrightarrow x^2-2x=0\\ \Leftrightarrow x.\left(x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x-2=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\\ \Rightarrow S=\left\{0;2\right\}\\ b,x^2-9-2x\left(x-3\right)=0\\ \Leftrightarrow x^2-4x^2+6x-9=0\\ \Leftrightarrow-3x^2+6x-9=0\\ \Leftrightarrow x^2-2x+3=0\\ \Leftrightarrow\left(x^2-2x+1\right)+2=0\\ \Leftrightarrow\left(x-1\right)^2=-2\left(vô.lí\right)\\ \Rightarrow Pt.vô.nghiệm\)
giải phương trình:
a) \(\sqrt{x+6}-\sqrt{x-2}=2\)
b) \(2\sqrt{x-3}-2x+3=0\)
a: ĐKXĐ: \(\left\{{}\begin{matrix}x+6>=0\\x-2>=0\end{matrix}\right.\Leftrightarrow x>=2\)
\(\sqrt{x+6}-\sqrt{x-2}=2\)
=>\(\left(\sqrt{x+6}-\sqrt{x-2}\right)^2=4\)
=>\(x+6+x-2-2\sqrt{\left(x+6\right)\left(x-2\right)}=4\)
=>\(2\sqrt{\left(x+6\right)\left(x-2\right)}=2x+4-4=2x\)
=>\(\sqrt{\left(x+6\right)\left(x-2\right)}=x\)
=>\(\left\{{}\begin{matrix}x>=0\\\left(x+6\right)\left(x-2\right)=x^2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>=2\\x^2+4x-12=x^2\end{matrix}\right.\)
=>x=3
b: ĐKXĐ: \(x-3>=0\)
=>x>=3
\(2\sqrt{x-3}-2x+3=0\)
=>\(\sqrt{4x-12}=2x-3\)
=>\(\left\{{}\begin{matrix}x>=\dfrac{3}{2}\\4x-12=4x^2-12x+9\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x>=3\\4x^2-12x+9-4x+12=0\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x>=3\\4x^2-16x+21=0\end{matrix}\right.\Leftrightarrow x\in\varnothing\)