｛2x -3y=6 ｛6 x+5y =1

6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y=3 x+2y=9 3/x+1=y y-x=3 y=2x-3 y-3x=1 2(x+1)-y=6 7x-5y=-9 x+y/2+x-y/3=5/6;x=y/6-x-y/3=1/2 3x+2y/4=2x+y/5=x-y+1/6 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 已知X,Y,满足(X+3Y)(X-3Y)=-10(Y^2-6/5)和2X(Y-1)+4(1/2X-1)=0 (1)已知x+y=6,x²-y²=5,求x-y的值（2）若x+y=3,x²+y² x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20