5X²-3Y²-(X²-Y²)-2(X²+4Y²)其中|X+2|+(Y+3)²=0,求值
问题描述:
5X²-3Y²-(X²-Y²)-2(X²+4Y²)其中|X+2|+(Y+3)²=0,求值
答
|X+2|+(Y+3)²=0x+2=0 x=-2y+3=0 y=-35X²-3Y²-(X²-Y²)-2(X²+4Y²)=5x²-3y²-x²+y²-2x²-8y²=2x²-10y²=2x2²-10x3²...能不能确定?确定