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(x-1)(x+2)=0
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\(\Leftrightarrow x^3+3x^2+3x+1-x^3+1-2=0\)
\(\Leftrightarrow3x^2+3x=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
\(\left(x+1\right)^3-\left(x-1\right)\left(x^2+x+1\right)-2=0\)
\(\Rightarrow x^3+3x^2+3x+1-x^3+1-2=0\)
\(\Rightarrow3x^2+3x=0\Rightarrow3x\left(x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)
\(\frac{3}{4}-\frac{x}{2}-1\frac{1}{2}=\)
\(\frac{3}{4}-\frac{x}{2}-\frac{3}{2}=0\)
\(\frac{3}{4}-\frac{x}{2}=0+\frac{3}{2}\)
\(\frac{3}{4}-\frac{x}{2}=\frac{3}{2}\)
\(\frac{x}{2}=\frac{3}{4}-\frac{3}{2}\)
\(\frac{x}{2}=-\frac{3}{4}\)
\(x:2=-\frac{3}{4}\)
\(x=-\frac{3}{4}.2\)
\(x=-\frac{3}{2}\)
=> x = -3
`a)2x^2+3(x-1)(x+1)=5x(x+1)`
`<=>2x^2+3x^2-3=5x^2+5x`
`<=>5x=-3`
`<=>x=-3/5`
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`b)(x-3)^3+3-x=0` nhỉ?
`<=>(x-3)^3-(x-3)=0`
`<=>(x-3)(x^2-1)=0`
`<=>[(x=3),(x^2=1<=>x=+-1):}`
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`c)5x(x-2000)-x+2000=0`
`<=>5x(x-2000)-(x-2000)=0`
`<=>(x-2000)(5x-1)=0`
`<=>[(x=2000),(x=1/5):}`
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`d)3(2x-3)+2(2-x)=-3`
`<=>6x-9+4-2x=-3`
`<=>4x=2`
`<=>x=1/2`
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`e)x+6x^2=0`
`<=>x(1+6x)=0`
`<=>[(x=0),(x=-1/6):}`
1.
\(\Leftrightarrow\left\{{}\begin{matrix}m< 0\\\Delta=\left(m+1\right)^2-4m\left(m-1\right)< 0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m< 0\\-3m^2+7m+1< 0\end{matrix}\right.\)
\(\Leftrightarrow m< \dfrac{7-\sqrt{61}}{6}\)
2.
\(\Leftrightarrow\left\{{}\begin{matrix}m>0\\\Delta'=4\left(m+1\right)^2-m\left(m-5\right)\le0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m>0\\3m^2+13m+4\le0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m>0\\-4\le m\le-\dfrac{1}{3}\end{matrix}\right.\)
Không tồn tại m thỏa mãn
x=1