2x+3y=5,4x^-9y^=20,4x^+9y^=?

4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 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 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 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (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 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+y=5 2x+3y-z=9 x-y+z=4 解下列方程组{4x-3y=5 2x+5y=9 {x+y=2 x-y=0 {x+2y=6 x-2y=-2 {5x-y=16 3x+2y=20 {2x+3y=-7 3x+2y=7 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 9y=3x-(x-1),4(x+y)-(2x+4)=8y 3X=5Y （X+Y)*3X=(2Y+X)*4+2*2 根据3（x+y)-2(x-y)=11,4(x+y)+3(x-y)=9可得出x+y= ,x-y=