﹛4x-2y=5 3x-4y=15 2分钟昂!

2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 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)/2+(x-y)/3=6 4(x+y)-3(x-y)=－2 0 求x,y分可以加. 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 x+2y=3（x+y）+5 3x-4y=4（x+y）-15 解方程x+y+(x+y/2)=15 3x+5y+4(x+y/2)=62 几道 数学题急啊 对了再加20分(x+y)^2-(x+y)^3(x-y)^2-(x-y)^3 (x-y)^2-(y-x)^32(x-y)-3(y-x)^24ab(a+b)^2-6a^2b(a+b)(x+y)(x-y)-(x+y)^28a(x-y)^2-4b(y-x)a=-5 a+b+c=-5.2求代数式a^2(-b-c)-3.2a(c+b)的值 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 求值(x-2y)²-4(x-2y)+2(x-2y)²-3(x-2y),其中x=-1,y=2分之110分钟之内回答者加5分,五分钟之内加10分 3X=5Y （X+Y)*3X=(2Y+X)*4+2*2 3=y:4,{2分之x+y=0.7好的加60分!还有：{x+y=5,{2x-y=m{y=x+a{x+2y=5a明确的答题过程 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x*x+2x+y*y-4y+5=0 x= y= （x+y）/2- x-y/2=6 3(x+y)=4(x-y)