Bài 1:
\(x^2-6x+9-y^2\)
\(=\left(x-3\right)^2-y^2\)
\(=\left(x-3+y\right)\left(x-3-y\right)\)
Bài 2:
\(x^2-x-12=0\)
\(\Leftrightarrow x^2-4x+3x-12=0\)
\(\Leftrightarrow x\left(x-4\right)+3\left(x-4\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-4\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x+3=0\\x-4=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-3\\x=4\end{array}\right.\)
1. x2+6x-9-y2
=-(x2-6x+y2)-32
=-(x-y)2-32
=(-x+y-3)(-x+y+3)
2. x2 - x - 12 = 0
=> x2 - 4x + 3x - 12 = 0
=> x( x - 4 ) + 3( x - 4 ) = 0
=> ( x + 3 )(x - 4 ) = 0
\(\Rightarrow\left[\begin{array}{nghiempt}x+3=0\\x-4=0 \end{array}\right.\) \(\Rightarrow\left[\begin{array}{nghiempt}x=-3\\x=4\end{array}\right.\)
Vậy x=-3; x=4
câu 1 :Phân tích được
(x-3-y).(x-3-y)
