900x+1200y+1100（60-x-y）= 61000

计算题求过程[答者必赞]900x+1200x+1100(60-x-y)-61000-1500 900x+1200y+1100（60-x-y）= 61000 x+y=7 900x=1200y , 900x=1200y x+y=7 x+y=7 900x=1200y 嗷 x+x+x+y=60 .x-y=4 {(x,y) |x|+|y| x>y?x:y ｛x/60+y/80=10,x/60+y/40=15、｛2x/3+3y/4=1/5,5x/6-5y/2=2、｛5/2(x+y）=1200,10/3（x+y）=1200｛4x+5y=98,5y-4x=2、｛x/3+y/4=54/60,y/4+x/5=42/60怎么解?{40-y=x-4 40-y=y-x x^/y-x-y^/y-x化简. 化简x(y-x)-y(x-y) 行列式计算 x y x+y y x+y x x+y x y|x y x+y ||y x+y x ||x+y x y | y/(x+y)-x/(x-y) 因式分解x(x+y)(x-y)-x(x+y)^2 x(x+y)(x-y)-x(x+y)的平方 x(x+y)(x-y)-x(x+y)² 因式分解 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 3.2x+60+x=y