tìm x thuộc Z
x.x+2=0
giúp mình với mình tick cho
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\(a,\Rightarrow4x\left(x^2-9\right)=0\\ \Rightarrow4x\left(x-3\right)\left(x+3\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\\ b,\Rightarrow\left(3x-5-x-1\right)\left(3x-5+x+1\right)=0\\ \Rightarrow\left(2x-6\right)\left(4x-4\right)=0\\ \Rightarrow2\left(x-3\right)4\left(x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
a) \(\Rightarrow4x\left(x^2-9\right)=0\)
\(\Rightarrow4x\left(x-3\right)\left(x+3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\)
b) \(\Rightarrow\left(3x-5-x-1\right)\left(3x-5+x+1\right)=0\)
\(\Rightarrow\left(2x-6\right)\left(4x-4\right)=0\)
\(\Rightarrow8\left(x-3\right)\left(x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
\(\Leftrightarrow y\left(x+1\right)+2\left(x+1\right)+9=0\)
\(\Leftrightarrow\left(x+1\right)\left(y+2\right)=-9\)
Để x;y nguyên thì:
\(\left\{{}\begin{matrix}x+1=3\\y+2=-3\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=-5\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x+1=-3\\y+2=3\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=-4\\y=1\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x+1=1\\y+2=-9\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0\\y=-11\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x+1=-9\\y+2=1\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=-10\\y=-1\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x+1=-1\\y+2=9\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=-2\\y=7\end{matrix}\right.\)
\(\left\{{}\begin{matrix}x+1=9\\y+2=-1\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=8\\y=-3\end{matrix}\right.\)
a. (2x + 1)2 - 4x2 + 2x2 - 2 = 0
<=> (2x + 1 - 2x)(2x + 1 + 2x) + 2(x2 - 1) = 0
<=> (4x + 1) + 2x2 - 2 = 0
<=> 4x + 1 + 2x2 - 2 = 0
<=> 2x2 + 4x - 2 + 1 = 0
<=> 2x2 + 4x - 1 = 0
<=> 2x2 + 4x = 1
<=> 2x(x + 2) = 1
Vì 1 chỉ có tích là 1 . 1 nên:
<=> \(\left[{}\begin{matrix}2x=1\\x+2=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=-1\end{matrix}\right.\)
\(a,\Leftrightarrow4x^2+4x+1-4x^2+2x^2-2=0\\ \Leftrightarrow2x^2+4x-1=0\\ \Leftrightarrow2\left(x^2+2x+1\right)-3=0\\ \Leftrightarrow2\left(x+1\right)^2-3=0\\ \Leftrightarrow\left(x+1\right)^2=\dfrac{3}{2}\\ \Leftrightarrow\left[{}\begin{matrix}x+1=\sqrt{\dfrac{3}{2}}\\x+1=-\sqrt{\dfrac{3}{2}}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{-2-\sqrt{6}}{2}\\x=\dfrac{-2+\sqrt{6}}{2}\end{matrix}\right.\)
\(b,\left(x-2\right)\left(x+2\right)-\left(x+3\right)^2-2x-5=0\\ \Leftrightarrow x^2-4-x^2-6x-9-2x-5=0\\ \Leftrightarrow-8x=18\\ \Leftrightarrow x=-\dfrac{9}{4}\)
Lời giải:
$f(x_1)-f(x_2)=2018mx_1-2018mx_2=2018m(x_1-x_2)$
$=f(x_1-x_2)$ (đpcm)
$f(kx)=2018m(kx)=k.2018mx=kf(x)$ (đpcm)
Vì \(x^2+1>0\) nên \(x^2-4=0\)
\(\Leftrightarrow x^2=4\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
a) x - 452 = 77 + 48
x - 452 = 125
x= 125 + 452
x= 577
b) x + 58 = 64 + 58
x + 58 = 122
x= 122 - 58
x= 64
c) x - 1 - 2 - 3 - 4 = 0
x= 0 + 4 + 3 + 2 +1
x= 10
\(x^2-4x+3=0\\ \Rightarrow\left(x^2-3x\right)-\left(x-3\right)=0\\ \Rightarrow x\left(x-3\right)-\left(x-3\right)=0\\ \Rightarrow\left(x-1\right)\left(x-3\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=1\\x=3\end{matrix}\right.\)
\(\Leftrightarrow-\dfrac{2}{5}\left(4x-3\right)^2=-\dfrac{5}{18}\)
\(\Leftrightarrow\left(4x-3\right)^2=\dfrac{25}{36}\)
\(\Leftrightarrow4x-3\in\left\{\dfrac{5}{6};-\dfrac{5}{6}\right\}\)
hay \(x\in\left\{\dfrac{23}{24};\dfrac{13}{24}\right\}\)
=> \(^{x^2}\)= 0-2
=> \(x^2\)= -2
=> x = (vô lý)
tk mk nha