2X+3Y=16 X+4Y=13
{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
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
(x+y)(x+2y)(x+3y)(x+4y)=-40
4x-(2x+y+16)/2=-6y 2x+3y=7-x-2y
3分之2(X-Y)-4分之X+Y=-1,6(X+Y)-4(2X-Y)=16
解方程组:2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16
解方程组 10(x-y)=3(x+y)+15 6(x+y)=4(2x-y)+16
已知集合A={(x,y)| (y-3)/ (x-1)=2,x,y∈R},B={(x,y)| 4x+ay=16,x,y∈
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1