5X+Y=3 X+5Y=2 求x和y.
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
|x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少
3x+2y=5 3y+2x=5 求x和y
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x+y=-5,x*x+y*y=19求xy和(x-y)*(x-y)的值
若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知(x+y):y=8:3,求2x+5y/3x-y和x^2-xy/y^2+3xy的值
已知x/3=y/5=z/4,求x+y+z/y和x+y-z/y-x的值,2种方法.急等.
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
已知x+y=-5,x*x*x+y*y=19,求xy和(x-y)的值
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5