2x+5y=3 5y+55x=100 5x+6y=?
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
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
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=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
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y
4x-2y-6y*-y-3x+5y* *=2 就是平方
x+y/2+x-y/3=5/6;x=y/6-x-y/3=1/2
若5x+3y=3x+4y=x+2y+6,则x+y=___
已知x,y满足约束条件{2x+5y>=10,2x-3y>=-6,2x+y