2道方程数学题{x-y=4 2x+y=5{2x-y=-4 4x-5y=-20
数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y
方程2分之x+y+2分之x-y=7,4(x+y)-5(x-y)=2
解方程x+y+(x+y/2)=15 3x+5y+4(x+y/2)=62
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
一道数学题:若x平方+y平方+2x-4y+5=0,先化简[(x/x-y)-1]/[y平方/x+y]
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*
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
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(