已知X-3Y+4=0.求分式X^2-XY-6Y^2/2X+4Y的值
问题描述:
已知X-3Y+4=0.求分式X^2-XY-6Y^2/2X+4Y的值
答
已知X-3Y+4=0,即X-3Y=-4
X^2-XY-6Y^2=(x+2y)(x-3y)
所以X^2-XY-6Y^2/2X+4Y=(x+2y)(x-3y)/2X+4Y=x-3y/2=-2