1.（2a+3b-1)(2a-3b+1) 2.（3y-1)(2y-3)+(6y-5)(y-4)

题目

1.（2a+3b-1)(2a-3b+1) 2.（3y-1)(2y-3)+(6y-5)(y-4)
3.(x-1)(x+3)-x(x-2) 4.

答案

1..（2a+3b-1)(2a-3b+1)=[2a+(3b-1)][2a-(3b-1)]=4aa-(3b-1)(3b-1)=4aa-9bb+6b-12.（3y-1)(2y-3)+(6y-5)(y-4)=6yy-11y+3+6yy-29y+20=12yy-40y+233.(x-1)(x+3)-x(x-2) =xx+2x-3-xx+2x=4x-3