(x+3y-2z)(x-3y-2z)-(x+3y-2z)^2 要过程还有一道：填空：（x-y+1）（x+y-5）=（x-y-2+__数学解答

(x+3y-2z)(x-3y-2z)-(x+3y-2z)^2 要过程
还有一道：
填空：（x-y+1）（x+y-5）=（x-y-2+_____)(x+y-2-_____)=[(x-2)-(____)]*[(x-2)+(____)]=(____）^2-(____)^2=_________

人气：157 ℃　时间：2020-01-25 16:28:39

解答

(x+3y-2z)(x-3y-2z)-(x+3y-2z)^2
=(x+3y-2z)[(x-3y-2z)-(x+3y-2z)]
=(x+3y-2z)(-6y)
=-6xy-18y²+12yz（x+3y-2z)^2的平方呢提取公因式(x+3y-2z)另一个因式是[(x-3y-2z)-(x+3y-2z)]（x-y+1）（x+y-5）=（x-y-2+3)(x+y-2-3)=[(x-2)-(y-3)]*[(x-2)+(y-3)]=(x-2）^2-(y-3)^2=x²-4x-y²+6y-5