(4x-9y)×(4x+9y)

4+12(x-y)+9(x-y)^ 9x+4y 81/8*(-x-y)^6*(x-y)^3*4/9(x+y)^4*(y-x)^2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 4(x+y)²-12(x+y)(x-y)+9(x-y)² 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 4(x+y)^2-12(x+y)(x-y)+9(+y)^2因式分解, 4(x-y+1)+y(y-2x)4x^4-13x²+9 9y=3x-(x-1),4(x+y)-(2x+4)=8y （4x-3y)(5x+2y)-2x(9x-5y) 等于多少 x>0 y>0 x+y=1,4/X+9/y最小值x>0 y>0 x+y=1,求4/X+9/y最小值 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 [6(x-y)的3次方*(x+y)的4次方-9*(x-y)的平方*(x+y)的3次方]根号[3(x-y)(x+y)] 根据3（x+y)-2(x-y)=11,4(x+y)+3(x-y)=9可得出x+y= ,x-y= (x+y)(x-y)+4(y-1) (9x+4y)(9x-4y)= (4x-9y)×(4x+9y) 9x^2-y^2+4x-4y快