Bài 3 :
a )
\(4x^2-4x=0\)
\(\Leftrightarrow4x\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}4x=0\\x-1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
Vậy \(x=0\) or \(x=1\)
b )
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1.
a.\(4x^2\left(5x^3-3x+1\right)\)
\(=20x^5-12x^3+4x^2\)
b.\(\left(5x^2-4x\right)\left(x-2\right)\)
\(=5x^3-10x^2-4x^2+8x\)
\(=5x^3-14x^2+8x\)
c.\(\left(x^2-2xy+y^2\right)\left(x-y\right)\)
\(=\left(x-y\right)^2\left(x-y\right)\)
\(=\left(x-y\right)^3\)
2.
a.Bạn xem lại đề câu này nhé!
b.\(x^2-y^2-3x-3y\)
\(=\left(x^2-y^2\right)+\left(-3x-3y\right)\)
\(=\left(x+y\right)\left(x-y\right)-3\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-3\right)\)
3.
a.\(4x^2-4x=0\)
\(4x\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}4x=0\\x-1=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\end{matrix}\right.\)
Vậy x=0 hoặc x=1.
