(3X+5Y) =9X^2-25Y^2(3X+5Y) =9X^2-25Y^2中间的空填什么

4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 5x=3y,(2x+y)的平方=5x(x+y)+9 3x-2y=9 x-3y=2 x+y=5 x+2y=3 y=x 2x+y=8 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 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) 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 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 (x-y)/4+(x+y)/5=1/4 (x+y)/9-(x-y)/3=//2(x-y)/4+(x+y)/5=1/4(x+y)/9-(x-y)/3=//2 {(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=? 解方程组 3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1 解方程组:{3(x+y)-2(x-y)=9,5(x+y)+2(x-y)=-1} 接二元一次4(x+y)-3(x-y)=9;5(x-y)+2(x+y)=11 5(x-y)^3*[-6/25(y-x)^3][-2/3(y-x^4]=