解方程组:X/30+Y/20+(75-X-Y)/40=2.5 X/30+(75-X-Y)/20+Y/40=2.8
解方程组x+y+√(x+y)=20;x²+y²=136
5(x+y)+3(x-y)=90 5(x+y)-3(x-y)=30,解二元一次方程组
解方程组 {2x-y-30=0 {30%x=20%y=8
解3元一次方程组:x+y+z=70 x/30+y/20+z/40=2/5 x/40+y/20+z/30=10/23
解方程组 30x=4/5y 40(x-1)=y+25
解方程组:x/2+y/3=1 x*20%+y*30%=14*10%
解方程组 x+y=1 20%x+30%y=25%x2
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
解方程组 x+2y=1.5,12(x+y)+15y=20
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
已知方程组4x+2y=1,20x+8y,求x,y
解下列方程组 x+y=420 30%x+40%y=160×80%