1.-1/4(xy+1)^2+1/16(1-xy)^22.已知xy=2,x^2+y^2=5求：（x-y）^2的值.3.The weather in Kunming is nice.The weather in Guangzhou is nice,too.(合并成一句)The weather in Kunming is ( ) nice ( ) that in Guangzhou.第一题是分解因式（完整

（1）3xy-4xy-(-2xy) [(xy-2)2次方-(-xy-1)(xy-4)]除(-3分之1xy) 【（2+xy）（xy-2）-xy（xy+1）+4】/（-2xy） 一道计算题! 计算：3xy-4xy-(-2xy)3xy-4xy-(-2xy)-1/3ab-1/4a²+1/3a²-（-2/3ab） 1/2xy(2/3xy²-2xy) 2xy(5xy的2次方+3xy-1) 2xy(5xy的2次方+3xy-1) 因式分解xy(xy+2)+6(xy+8)-4(x+y-2)^2-16(x+y+1)谢谢 先化简,再求值：{（xy-2）^2+4xy-4}/(-xy),其中x=1.,y=-1/25 （xy^2)^m+1次方/xy^2 (6-2xy)(2-6xy)=4(3-xy)(1-3xy)如题,(6-2xy)(2-6xy)怎样化到4(3-xy)(1-3xy)? 搜索[4(xy-1)二次方-(xy+2)(2-xy)]除以4分之1xy,其中X=-2,Y=5分之1.怎么算 [(xy-2)(-xy-2)-4(xy-1)^2]除以(-xy),其中x=20,y=-25分之1 化简 2（xy-xy²+3）-（-4xy²+xy-1） 其中,x等于--4,y等于-3 (-1/2xy^2)^2(3xy-4xy^2+1) 计算（-1/2xy²）²（3xy-4xy²+1） xy[4xy-2(xy+1/2x的2次方y)] XY(XY+3)+(XY+4)+4(X+Y+1)-(X+Y+2)