若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值
问题描述：
若x-y/x+y=5,求x-y/2x+2y+5x+5y/3x-3y的值
答
(x-y)/(x+y)=5,
(x+y)/(x-y)=1/5
(x-y)/(2x+2y) + (5x+5y)/(3x-3y)
= 1/2 * (x-y)/(x+y) +5/3 * (x+y)/(x-y)
= 1/2 * 5 + 5/3*1/5
= 5/2 + 1/3
= 17/6
答
x-y/x+y=5
(x+y)/(x-y)=1/5
x-y/2x+2y+5x+5y/3x-3y
=1/2(x-y)/(x+y)+5/3(x+y)/(x-y)
=5/2+1/3
=17/6
答
若x-y/x+y=5
则x-y=5(x+y)
所以求x-y/2x+2y+5x+5y/3x-3y
=5(x+y)/[2(x+y)]+5(x+y)/3(x-y)
=5/2+5(x+y)/[3*5(x+y)]
=5/2+1/3
=17/6
答
﹙x－y﹚/﹙2x＋2y﹚ ＋﹙5x＋5y﹚/﹙3x－3y﹚
＝1/2×﹙x－y﹚/﹙x＋y﹚＋5/3×﹙x＋y﹚/﹙x－y﹚
＝1/2 ×5＋5/3×1/5
＝5又1/2.