4x+5y=9 2x-3y=-5 怎么算?

二元一次方程(x+y)/2+(x-y)/3=6,4(x+y)-5(x-y)=2怎么算 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y怎么解 4x+5y=9 2x-3y=-5 怎么算? 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? (y-x)(x-y)^3(y-x)^5怎么算 2x-y=8 3x+2y=5与3x+2y=1 3x-4y=-11用加减法怎么算? 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(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 5x+4y=22 4x+y=3y+x 怎么解 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 接二元一次4(x+y)-3(x-y)=9;5(x-y)+2(x+y)=11 x/5-y/2=2 2x+3y=4 怎么算 方程{5x+4y=-3,2x-3y=8}怎么算 {x/2-y/5=20 {2x+3y=4 怎么算