2x^2-7x+7=0 2y^2-7y+8=0
y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,
{2x+y/3-2y=0 2(2x+y)-5=7y
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
已知实数x.y满足根号(x+y-8)+根号(8-x-y)=根号(3x-y-4)+根号(x-2y+7),求x,y
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
若(x-2)*2+15y-11=0,求-3(2x-y)-{7x-〔6x+2y-(10x-8y)〕
若(x-2)的平方+15y-11=0,求代数式-3(2x-y)-{7x-[6x+2y-(10x-8y
已知x-y不等于0,x^2-x=7,y^2-y=7,求x^3+y^3+x^2y+xy^2的值
2x-y=7,3x+y=8
已知有理数x,y满足1/2|x-y|+|y-1/2|=0 求3x+7y
已知:x,y满足|2x-y|+|y-1/2|=0,求7x-3y的值.