来自陶大军的问题
1.如果1/x-1/y=3,试求2x-3xy-2y/x-2xy-y的值.2.若x²+3x+1=0,试求x²+1/x²的值.
1.如果1/x-1/y=3,试求2x-3xy-2y/x-2xy-y的值.
2.若x²+3x+1=0,试求x²+1/x²的值.
1回答
2020-03-28 15:53
1.如果1/x-1/y=3,试求2x-3xy-2y/x-2xy-y的值.2.若x²+3x+1=0,试求x²+1/x²的值.
1.如果1/x-1/y=3,试求2x-3xy-2y/x-2xy-y的值.
2.若x²+3x+1=0,试求x²+1/x²的值.
(1)1/X-1/Y=3(Y-X)/XY=3Y-X=3XY,X-Y=-3XY(2X-3XY-2Y)/(X-2XY-Y)=[2(X-Y)-3XY]/(X-Y-2XY)=(-6XY-3XY)/(-3XY-2XY)=(-9XY)/(-5XY)=9/5(2)X²+3X+1=0X²+1=-3X由于X不等于0,两边同时除...