【1】5x-3y=12 【2】9x-5y+z=-6 3x+4y=-8 9x+y+4z=3 -9x+3y-5z=0

4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? (x-y)/4+(x+y)/5=1/4 (x+y)/9-(x-y)/3=//2(x-y)/4+(x+y)/5=1/4(x+y)/9-(x-y)/3=//2 解方程组 3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1 解方程组:{3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1} 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 4(x+2)=1-5y 4(x+y)-3(x-y)=12 解方程组: ｛3x+2y=13 3x-2y=5 ｛x-y/3=x+y/2+1 2x-5y=9 5x=3y,(2x+y)的平方=5x(x+y)+9 (3x+2y)(4x-5y)-12(x+y)(x-y)+7xy,其中x=2011,y=-1, 计算：1.y/4x²-1/12y²+1/6xy 2.3/x-6/1-x-x+5/x²-x3.x/x-y×y²/x+y-x四次方y/x四次方-y四次方÷x²/x²+y²解方程：1.x-1/（x-2）+1=1/2-x2.x+1/x-1-4/x²-1=13.1/x+3-2/3-x=1/x²-9 3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 解方程组 2x-y=5 2y/x-x/y=12x-y=52y/x-x/y=1 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 x+y=1 5x-2y=8 3x-y=7 2x-y=3x表示y和用y表示x (x+2y)(x-2y)-(2x-y)的平方+(3x-y)(2x-5y)其中x=-1 y=13分之1