{x+y=5{3x-7y=11
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
{x+y=5{3x-7y=11
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
3x+2=y 5X+4=Y 7X+6=Y 9X+8=y 11x=y要如何计算
3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y
y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,
3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y 联立方程 有的话
{3x-2y=3,2x+2y=17 {4x-2y=14,5x+y=7 {x+3y=6,2x-3y=3 {2x+3y=11
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
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
(5x+3y)(3y-5x)-(4x-y)(4y+x)=
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5