共3道：1,x2-y2-z2-2yz2,x2y2-0.25(x2+y2)23,x2-9y2-2x+6y.

Question

共3道：
1,x2-y2-z2-2yz
2,x2y2-0.25(x2+y2)2
3,x2-9y2-2x+6y.

Answer 1

1.x2-y2-z2-2yz = x2-(y2+2yz+z2)=x2-(y+z)2 =(x+y+z)(x-y-z)
2.x2y2-0.25(x2+y2)2 = -0.25(x2-y2)2
3.x2-9y2-2x+6y = (x-1)2 - (3y-1)2
按照你的格式写的,x2后面的2表示平方,其他类同.