x+y=1,则0.5x²+xy+0.5y²= ?

x+y=1,则0.5x²+xy+0.5y²= ? 若x-y=1,xy=5,则x²y-xy²=? 若x+y=10 xy=-1 则x²+y²=(x+y)²-2xy= 化简并求值 xy-2{xy-[3x²y-(xy²+0.5xy)]+4x²y},其中x=1, 已知x+y=1,求0.5x²+xy+0.5y²的值 如果x+y=1,那么0.5x²+xy+0.5y²的值是多少 x²+xy/(x-4y)(x+y),其中x=4,y=-1 一.x-y=2,则x²-2xy+y²= 二.x-y=-1,xy=3,则x³y-2x 已知x+y=1,xy=-二分之一,求x（x+y)(x-y)-x(x+y)² 已知x+y=5,xy=3,x³+y³=(x+y)(x²-xy+y²),则1/x& 已知实数x,y满足5x²+2y²+1=6xy+4x-2y,则x²-xy+2000y 1\x+1\y=8\x+y,则y\xy+x\xy=?