已知x2+3xy-4y2=0 (y不等于0),求(x-y)\(x+y)的值.

已知x2+3xy-4y2=0 (y不等于0),求(x-y)\(x+y)的值.
已知x2+3xy-4y2=0 (y不等于0),求(x-y)\(x+y)的值.

已知x2+3xy-4y2=0 (y不等于0),求(x-y)\(x+y)的值.
x^2+3xy-4y^2=0(y≠0),因式分解为(x+4y)(x-y)=0
所以x=-4y 或 x=y
则当x=-4y时,(x-y)/(x+y)=(-4y-y)/(-4y+y)=5/3
当x=y时,x-y/x+y=0

5/3或者是0,因为X的平方+3XY+4Y的平方=0则X+4Y=0或者X-Y=0所以(X-Y)/(X+Y)=0或者5/3.