若(x+y)²=9,(x-y) ²=5,则xy=?
若x-y=1,xy=5,则x²y-xy²=?
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知有理数x,y满足xy=4,x+y=7,则x²y+xy²=()?
已知:x²-xy=9,xy-y²=5,则x²-2xy+y²=(),3x²
若x+y=10,xy=24,则x²+y²=?(x-y)²=?
(xy-2y)(xy+2y)-(x-y)²-x²y² 其中x=5/2 y=- 3/5 先化
2x²-3xy=y²=0(x,y不得o)求x/y+y/x
已知(x+3)+丨X-y+10丨=0 ,求5x²y-[2x²y-(3xy-xy²)-3x&
若x+y=10 xy=-1 则x²+y²=(x+y)²-2xy=
若x²+xy+5y=3,y²+xy+5x=-3,求x+y的值.
若x²+xy+5y=3,y²+xy+5x=-3,求x+y的值
若x²+xy+5y=3,y²+xy+5x=-3,求x+y旳值