填空：1.（-2a）²·（-9a²b³）=_______
2.(3/4x²y-5zyz²)·（-3/5xy²z）=________
3.(-9ab)·（1/3ab+1/6a-1）=__________4.(-3/4x²y-2/3xy²-5/6y³)·（-12xy）=____________
5.[-(a²b)²]³·（12a^3b^4-6a²b³）=__________6.(x-2)(2x+1)=___________
7.(3m-n)(m-2n)=________________8.(a+2b)(5a+3b)=____________
9.5(x-1)(x+3)=_____________10.(2x-3)(x+4)=______________
11.(x+3y+4)(2x-y)=___________12.(-x+6)(-x+7)=______________
13.(x-4)(x-3)-(x-2)(x-5)=______________14.(x-2y)(x+3y)-(-x+y)(-x-y)=_____________