3x-7y=0 5(x-2)+3y+6)=1

若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 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 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 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组, 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){x+2y=0,3x+4y=6(2){5x+6y=16,7x-9y=5（3）{9x-11y+1=0,4x-5y-3 请帮我做几道方程1、x+2y=0 3x+4y-6=02、3x+2y=-2 3x-y=43、6x+7y=-19 5y-6x 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值