4x+7y=-19,4x-5y=17
{3x-2y=3,2x+2y=17 {4x-2y=14,5x+y=7 {x+3y=6,2x-3y=3 {2x+3y=11
2X+Y+Z=10,X+2Y+Z=-6,X+Y+2Z=8 5X+4Y-3Y=13,2X-3Y+7Z=19,3X-Y=2X
(5x+3y)(3y-5x)-(4x-y)(4y+x)=
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
已知:4x = 5y,求(x+y) :y
x-y+5x-4x= ?
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
方程2分之x+y+2分之x-y=7,4(x+y)-5(x-y)=2
x+y=5; x^y+y^x=17
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
4x+7y=-19,4x-5y=17
4x+7y=-19 4x-5y=-17