27×700+X/3×y/400=750

27×700+X/3×y/400=750 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? x+x+y+y+y=21 ,x+x+y+y+y+y+y=27 ,x ,y=? （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x 1.5（x+y）+3（x-y）=27（x+y）-3（x-y）=-62.x-y/7 - x+y/10 =1/22(x-y)-5(x+y)=3所谓细节决定成败, 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做. x+y=700,400-y=2x,求x和y. 解方程组 {3(x+y)-4(x-y)=11 {2(x-y)+5(x+y)=27 解方程组 {3(x+y)-4(x-y)=11 {2(x-y)+5(x+y)=27全过程、快 x+y=27 3y+x=3 请问x和y各是多少 x+y/2=z+x/3=y+z/4 x+y+z=27 2^x=4^(y-1) 27^y=3^(x+1)求x-y X+Y=10,X^3+Y^3=400,求X^2+Y^2 已知x+y=10,x^3+y^3=400,求x^2+y^2 (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=