化简求值①化简:4ab+8-2b2-9ab-6②先化简,再求值:已知3x2y-[2x2y-3(2xy-x2y)-xy],
化简求值①化简:4ab+8-2b2-9ab-6②先化简,再求值:已知3x2y-[2x2y-3(2xy-x2y)-xy],
化简求值:2(x2y+xy)-3(x2y-xy)-4x2y,其中x=-1,y=1.
先化简后求值:4x2y-[6xy-3(4xy-2)-x2y]+1,其中x=2,y=-12
先化简,再求值 3x2y-[2xy-2(xy-32
2(x2y+xy)-3(x2y+xy)-4x2y其中x=-2,y=12
先化简,再求值(3x2y-2xy2)-(xy2-2x2y),其中x=-1,y=2.
4x2y-{x2y-「3xy2 – 1/ 2(4x2y-8xy2)+x2y」}-5xy2
已知A=x3-2y3+3x2y+xy2-3xy+4,B=y3-x3-4x2y-3xy-3xy2+3,C=y3+x2y+2
先化简,后求值.[2x(x2y-xy2)+xy(xy-x2)]÷x2y,其中x=2013,y=2012.
已知A=8x2y-6xy2-3xy,B=7xy2-2xy+5x2y,若A+B-3C=0,求C-A.
化简并求值:(2x2y-2xy2)-[(-3x2y2+3x2y)+(3x2y2-3xy2)],其中x=−12,y=2
先化简,再求值:x2y-[4x2y-(xyz-x2z)-3x2z]-2xyx,其中x的倒数等于其本身,|y|=3,x2=