已知(x+y)²=9 (x-y)²=5 问 xy等于多少
已知关于x、y的方程组3(x²+y²)-5xy=6;2(x²+y²)+xy=17
已知x²-xy-y²=0,且x≠0,y≠0.求代数式(x²-2xy-5y²)/(
已知(x+2)²+|x+y+5|=0,求3x²y+{-2x²y-[-2xy+(x²
问已知x²+y²=7,xy=-2,求5x²-3xy-4y²-11xy-7x&su
已知x²y²+x²+y²=10xy-16 求x,y
已知X²+Y²-8X-10Y+41=0,求Y/(X²-XY)+X/(Y²-XY)
2道初二代数题1.已知X+Y=3.xy=-5 (1)x²+y²,(2)x²-xy+y&su
1、已知xy满足(x+1)²+1y+21=0试求-2xy·5x²y+(0.5x²y&sup
已知X²-5XY+6Y²=0,求(X²+3XY)\2Y²的值
已知2x²-3y²=xy,(xy≠0),求值(4xy-x²)/(xy+2y²)的
已知x+y=-3 求(2x²+xy+3y²)-(x²-xy+2y²)的值
已知x/y=2,求(x²-xy+3y²)/(x²+xy+6y²)的值