x+y=6 10x+y≤42

x+y=6 10x+y≤42 求f(x,y)=x+y+7的最大值,使(x,y)满足x+2y≤10,2x+y≥6,y≥0 (x+y)/6+(x-y)/10=1,(x+y)/6-(x-y)/10=5 {6/x+y+10/x-y=30 6/x+y-10/x-y=-1 x,y 满足x(x-2)-y(y-6)=-10,求x,y的值 这道题真么做X Y 6 10 Y X如果（X+Y) (Y+X) =(X+6) ,且（X-Y)X+6(X-Y)=(X-Y) ,求X +Y 的值. x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x^2+4y^2-6x+4y+10=0,求x^4-y^4/(x+2y)(x-2y)*x+2y/xy^2+y^3除以（x^2+y^2/y)^2的值 {x=5y 3x+6y=42 化简 x / y(x+y) - y / x(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 10y+x/10x+y=5/6 x+y=10,6x+4y=46 x+y=10;8x+6y=66 解方程组x+y/6+x-y/10=3,x+y/6+y-x/10=-1x+y/6+x-y/10=3 ①x+y/6+y-x/10=-1 ② 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 解方程组 10（x-y)=3(x+y)+15 6(x+y)=4(2x-y)+1610（x-y)=3(x+y)+156(x+y)=4(2x-y)+16 解方程组 10（x-y)=3(x+y)+15 6(x+y)=4(2x-y)+1610（x-y)=3(x+y)+156(x+y)=4(2x-y)+16分开的。