若x² +xy+y² =14,x² -xy+y²=28求x+y的值

若x²+xy-2y²=0,则x²+3xy+y²/x²+y² 若x² +xy+y² =14,x² -xy+y²=28求x+y的值 若x²+xy+y²=14,x²-xy+y²=28,求x+y的值 0.5x²+xy+0.5y² 因式分解：x²-xy-12y² 4x²y-xy² -9x²-y²+6xy x²-2xy+y²-9 6xy²-9x²y-y²因式分解 x²+xy-2y²=0则x²+3xy+y²/x²+y² 若|x+y-5|+(xy-6)²=0,求x²+y²的值. 若x²+y²+4x-10y+29=0,则x²y+xy²= 因式分解 x²-2xy+y²-z² 计算：4xy²-3x²y-{3x²y-[2xy²-4x²y+2(x²y-2xy²)]急 （x²+y²)²-x²y²=(x²+y²)²-(xy)²=(x²+y²+xy)(x²+y²-xy)=(x+y)²(x-y)²-xy+xy=(x+y)²(x-y)² x²-4y²/x²+2xy+y²÷x+2y/2x²+2xy x²y²-x²y-xy²+x+y-1因式分解 已知x²y²+x²+y²=10xy-16 求x,y