Bài 1:
a) \(=3x\left(x-y\right)+5\left(x-y\right)=\left(x-y\right)\left(3x+5\right)\)
b) \(=z\left(x+y\right)-5\left(x+y\right)=\left(x+y\right)\left(z-5\right)\)
c) \(=\left(x-y\right)\left(x+y\right)-\left(x-y\right)=\left(x-y\right)\left(x+y-1\right)\)
d) \(=3\left[\left(x+y\right)^2-z^2\right]=3\left(x+y-z\right)\left(x+y+z\right)\)
Bài 2:
a) \(\Rightarrow\left(x-3\right)^2+2\left(x-3\right)=0\)
\(\Rightarrow\left(x-3\right)\left(x-1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)
b) \(\Rightarrow\left(x-5\right)\left(x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=5\\x=-1\end{matrix}\right.\)
a) \(3x^2+5x-3xy-5y\)
\(=\left(3x^2-3xy\right)+\left(5x-5y\right)\)
\(=3x\left(x-y\right)+5\left(x-y\right)\)
\(=\left(3x+5\right)\left(x-y\right)\)
b) \(xz+yz-5\left(x+y\right)\)
\(=\left(xz+yz\right)-5\left(x+y\right)\)
\(=z\left(x+y\right)-5\left(x+y\right)\)
\(=\left(z-5\right)\left(x+y\right)\)
