3x+4Y=59 6x+6Y=55
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
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
{4/(x+y)+6/(x-y)=3 {9/(x-y)-1/(x+y)=1
【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2=
已知x,y满足x²+y²-4x+6y+13=0则(3x+y)²-(3x+y)(3x-y)的
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
已知x,y满足:x平方+y平方-4x+6y+13=0求(3x+y)-3(3x-y)(x+y)-(x-3y)(x+3y)=
4x-2y-6y*-y-3x+5y* *=2 就是平方
若5x+3y=3x+4y=x+2y+6,则x+y=___