1、3x+y=22 2、3x-2y=9 3、4x+3y=25 4、2y=7x+3 5、4x-3y=14 5-2y=0 x

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 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 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 数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y 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 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 (x+y)(x+2y)(x+3y)(x+4y)=-40