已知X^2-4Y^2=-15,X+2Y=3,求X,Y的值
问题描述:
已知X^2-4Y^2=-15,X+2Y=3,求X,Y的值
答
X^2-4Y^2=(x+2y)(x-2y)=3(x-2y)=-15,
x-2y=-5
X+2Y=3
x=-1
y=2