1. (x-y+z)(-x-y-z)=y^2-(x+z)^2=y^2-x^2-z^2+2xz2. (6分之1y2)-(3分之1y)-(2分之1)=(1/6)(y^2-2y-3)=(1/6)(y-3)(y+1)3. 9-x2-2xy-y2=9-(x+y)^2=(3+x+y)(3-x-y)4. Can you buy a book _____ Garfied?D
A.calls
B.calling
C.call
D.called5. --Where is John Amy? --She has _____ , so she didn't ...
