Help me please!!!
Tìm x:
|2x+3|-|x-3|= 0
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a,\(x^3-x=0\Rightarrow x\left(x^2-1\right)=0\Rightarrow x\left(x+1\right)\left(x-1\right)=0\)
b,\(x^2-2x+x-2=0\Rightarrow x\left(x-2\right)+\left(x-2\right)=0\Rightarrow\left(x-2\right)\left(x+1\right)=0\)
c,\(x^2-6x+8=x^2-4x-2x+8=x\left(x-4\right)-2\left(x-4\right)=\left(x-4\right)\left(x-2\right)\)
\(x^3-x=0\)
\(\Leftrightarrow x\left(x^2-1\right)=0\)
\(\Leftrightarrow x\left(x-1\right)\left(x+1\right)=0\)
x=0 hoặc x-1=0=> x=1 hoặc x+1=0 => x=-1
\(x^2-2x+x-2=0\)
\(\Leftrightarrow x\left(x-2\right)+\left(x-2\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(x+1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=0\\x+1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-1\end{cases}}}\)
\(x^2-6x+8=0\)
\(\Leftrightarrow x^2-2x-4x+8=0\)
\(\Leftrightarrow x\left(x-2\right)-4\left(x-2\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(x-4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=0\\x-4=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=0\\x=4\end{cases}}}\)
x2 + 2x = 0
=> x(x + 2) = 0
=> \(\orbr{\begin{cases}x=0\\x+2=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=0\\x=-2\end{cases}}\)
(x - 2) + 3.x2 - 6x = 0
=> (x - 2) + 3x2 - 3x . 2 = 0
=> (x - 2) + 3x.(x - 2) = 0
=> (1 + 3x)(x - 2) = 0
=> \(\orbr{\begin{cases}1+3x=0\\x-2=0\end{cases}}\)
=> \(\orbr{\begin{cases}x=-\frac{1}{3}\\x=2\end{cases}}\)
Câu a :
\(x^2-2x-3=0\)
\(\Leftrightarrow x^2-x+3x-3=0\)
\(\Leftrightarrow x\left(x-1\right)+3\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\Rightarrow x=1\\x+3=0\Rightarrow x=-3\end{matrix}\right.\)
Câu b :
\(2x^2+3=-5x\)
\(\Leftrightarrow2x^2+3+5x=0\)
\(\Leftrightarrow2x^2+2x+3x+3=0\)
\(\Leftrightarrow2x\left(x+1\right)+3\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+1=0\Rightarrow x=-1\\2x+3=0\Rightarrow x=-\dfrac{3}{2}\end{matrix}\right.\)
Mấy câu sau khó quá ko bt làm :)
\(\left(x-3\right)^2-\left(x^2-3x\right)=0\)
\(\left(x-3\right).\left(x-3\right)-x.\left(x-3\right)=0\)
\(\left(x-3\right).\left(x-3-x\right)=0\)
\(\left(x-3\right).3=0\)
\(x-3=0=>x=3\)
vì \(x^4+2x^2+1=\left(x^2+1\right)^2\) mà \(x^2\ge0\Rightarrow x^2+1>0\Rightarrow\left(x^2+1\right)^2>0\)với mọi x.Nên x-3=0 .Từ đó suy ra x=3
|2x+3|=|x-3|
(2x+3)2=(x-3)2
4x2+12x+9=x2-6x+9
3x2 + 18x = 0
x=0 hoặc x=-6