已知4x²+y²-4x+6y+10=0,怎么求4x²-12xy+9y²
问题描述:
已知4x²+y²-4x+6y+10=0,怎么求4x²-12xy+9y²
答
4x²+y²-4x+6y+10
=(2x-1)²+(y+3)²=0
2x-1=0,
y+3=0
x=1/2
y=-3
4x²-12xy+9y²
=(2x-3y)²
=(1+9)²
=100