已知x/2=y/3,你能用两种方法计算x^2-y^2/x^2-2xy-3y^2的值吗?
问题描述：
已知x/2=y/3,你能用两种方法计算x^2-y^2/x^2-2xy-3y^2的值吗?
答
已知x/2=y/3,你能用两种方法计算x^2-y^2/x^2-2xy-3y^2的值吗?x/2=y/3x=2y/3y=3x/2(x²-y²)/(x²-2xy-3y²)=(x-y)(x+y)/(x-3y)(x+y)=(x-y)/(x-3y) 当x=2y/3时=(2y/3-y)/(2y/3-3y)=-1/3y/(-7/3y)=1/7...