20%X+30%Y+277=2000

20%X+30%Y+277=2000 [2000+20(x-y)]/x+y = (2000-20y)/y 怎么化简 1=x+y 2=20x+30y 40X+30Y=2200 X>20 Y x+y=20-6 3x+y=30x、y是多少 3（x+y)+2(x-3y)=20,30%x+60%y=10%*60 请问60%x+20%y=30%(x+y) 怎么得到x:y=1:3 |x|+|y|=30 2|x|-3|y|=20 求x,y x+y=27 20x+30y=660 求x、y值 {x+y=27 20x+30y=6.6 求x、y值? x+x=y+30 x+x+x+y=20 x+x+y=14 x=?y=? 2x-y=30,30%x+20y%y=8解方程组 x+y=20,x-y=10,y= {6/x+y+10/x-y=30 6/x+y-10/x-y=-1 x+y=30,x方+y方=458,求x,y求x,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