(2x-5y)(3x-y)=多少?

(2x-5y)(3x-y)=多少? x-y/3=x+y/2 2x-5y=7等于多少 |x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) （4x-3y)(5x+2y)-2x(9x-5y) 等于多少 (x-y)^2·(y-x)^3=多少? x-y)^2·(y-x)^3=多少? 2x+3y=19.5 5x+6y=45求x=多少 y=多少 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 3Y＝2X X/Y=3/2 2X/(X+Y)=2X/(X+2/3X)=6/5 等于多少 3x+2y=36 5x+2y=52求x=?y=?算x=多少y等于多少? 已知x+y=6,x-y=5,则x^2-y^2等于多少