已知y²=3.14,（x-z）²=0.14,则（x+y-z）（x-y-z）=

已知y²=3.14,（x-z）²=0.14,
则,y^2-(x-z)^2=3.14-0.14=3
[y+(x-z)][y-(x-z)]=3
(y+x-z)(y-x+z)=3
-（x+y-z)(x-y-z)=3
所以,（x+y-z）（x-y-z）=-3
若（a-b-1）（a-b-3）=5
则,（a-b)^2-4(a-b)+3=5
(a-b)^2-4(a-b)=2
那么,（a-b-2）²
=[(a-b)-2]^2
=（a-b)^2-4(a-b)+4
=2+4
=6