一、整式化简1.23a3bc2-15ab2c+8abc-24a3bc2-8abc=______.2.(2x2-3xy+4y2)+(x2+2xy-3y2)=______.3.2a-(3a-2b+2)+(3a-4b-1)=______.4.2x-(x+3y)-(-x-y)-(x-y)=______.5.5-(1-x)-1-(x-1)=______.6.(
)+(4xy+7x2-y2)=10x2-xy.7.(4xy2-2x2y)-(
)=x3-2x2y+4xy2+y3.8.已知A=x3-2x2+x-4,B=2x3-5x+3,计算A+B=______;A-B=______.9.一个多项式减去3m4-m3-2m+5得-2m4-3m3-2m2-1,则这个多项式等于______.10.-(2x2-y2)-[2y2-(x2+2xy)]=______.11.(-y+6+3y4-y3)-(2y2-3y3+y4-7)=______.12.4x2-[7x2-5x-3(1-2x+x2)]=______.13.2a-b2+c-d3=2a+(
)-d3=2a-d3-(
).14.[5a2+(
)a-7]+[(
)a2-4a+(
)]=a2+2a+1.15.已知x<0,y>0,则|1-x+y|-|x-y|=______.16.已知x<0,y<0,则|x+y|-|5-x-y|=______.17.一个多项式加上-3x2y+2x2-3xy-4得2x2y+3xy2-x2+2xy,这个多项式为______.18.-2(3x+z)-(-6x)+(-5y+3z)=______.19.3a-(2a-4b-6c)+3(-2c+2b)=______.20.当2y-x=5时,5(x-2y)2-3(-x+2y)-100=______.二、因式分解1.8-2x22.16x2-813.x2(x-y)+y2(y-x)4.