Bài 1:tìm x thuộc Z
a)x.(x-1)=0
\(\Leftrightarrow\left[\begin{matrix}x=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\x=1\end{matrix}\right.\)
Vậy: \(x=0;1\)
b)(x-3).(x+4)=0
\(\Leftrightarrow\left[\begin{matrix}x-3=0\\x+4=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=3\\x=-4\end{matrix}\right.\)
Vậy: \(x=3;-4\)
c)(2x-4).(x+2)=0
\(\Leftrightarrow2\left(x-2\right).\left(x+2\right)=0\)
\(\Leftrightarrow\left[\begin{matrix}x-2=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
Vậy: \(x=2;-2\)
d)(x+1)^2.(x-2)^2=0
\(\Leftrightarrow\left[\begin{matrix}x+1=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=-1\\x=2\end{matrix}\right.\)
Vậy: \(x=-1;2\)
e) x(x+1).(x+2)^2.(x+3)^3=0
\(\Leftrightarrow\left[\begin{matrix}x=0\\x+1=0\\x+2=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\x=-1\\x=-2\\x=-3\end{matrix}\right.\)
Vậy: \(x=0;-1;-2;-3\)
f)(x-9)^5.(x-5)^8=0
\(\Leftrightarrow\left[\begin{matrix}x-9=0\\x-5=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=9\\x=5\end{matrix}\right.\)
Vậy: \(x=9;5\)
g)x(x+100)^10.(x+2000)^20.(x+300)^300=0
\(\Leftrightarrow\left[\begin{matrix}x=0\\x+100=0\\x+200=0\\x+300=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\x=-100\\x=-200\\x=-300\end{matrix}\right.\)
Vậy: \(x=0;-100;-200;-300\)
h)(x-2)^2=0
\(\Leftrightarrow x-2=0\)
\(\Leftrightarrow x=2\)
Vậy: \(x=2\)