câu 22:
a) \(=5xy\left(y+xz-3\right)\)
b) \(=z^2-\left(x^2-2xy+y^2\right)=z^2-\left(x-y\right)^2=\left(z-x+y\right)\left(z+x-y\right)\)
câu 23:
a) \(2x\left(x-3\right)-\left(x-1\right)\left(1+2x\right)=9\\ \Leftrightarrow2x^2-6x-\left(x-1+2x^2-2x\right)=9\\ \Leftrightarrow2x^2-6x-\left(2x^2-x-1\right)=9\\ \Leftrightarrow2x^2-6x-2x^2+x+1=9\\ \Leftrightarrow-5x=8\\ \Leftrightarrow x=\dfrac{-8}{5}\)
b) \(\Leftrightarrow x\left(x+9x+8\right)=0\\ \Leftrightarrow x\left(x+1\right)\left(x+8\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=-1\\x=-8\end{matrix}\right.\)