解:(1)原式=3x﹣6y﹣3x+y =﹣5y; (2)(﹣2ab)(3a2﹣2ab﹣b)2= (﹣2ab)[(3a 2﹣2ab)﹣b]2=﹣2ab(9a4﹣12a3b+4a2b2+b2﹣6a2b+4ab2), =﹣18a5b+24a4b2﹣8a3b3﹣2ab3+12a3b2﹣8a2b3 (3) =﹣3﹣1+1 =﹣3; (4)(a+b﹣3)(a+b+3) =[(a+b)﹣3][(a+b)+3] =(a+b)2﹣9 =a2+2ab+b2﹣9; (5)(x﹣1)(x+3)﹣(x﹣2)2=x2+3x﹣x﹣3﹣(x2﹣4x+4) =x2+2x﹣3﹣x2+4x﹣4 =6x﹣7. |