解:①+②33(x+y)+56(x-y)=(x-y)/(x2+y2)…③①-②56(x+y)-33(x-y)=-(x+y)/(x2+y2)…④③÷④[33(x+y)+56(x-y)]/[56(x+y)-33(x-y)]=-(x-y)/(x+y)令x+y=a,x-y=b∴(33a+56b)/(56a-33b)=-a/b∴33ab+56b2=-56a2+33ab∴a2+b2=0∴(x+y)2+(x-y)2=0∴x2+y2=0依题意,x2+y2≠0∴此方程无实数解 |
解:①+②33(x+y)+56(x-y)=(x-y)/(x2+y2)…③①-②56(x+y)-33(x-y)=-(x+y)/(x2+y2)…④③÷④[33(x+y)+56(x-y)]/[56(x+y)-33(x-y)]=-(x-y)/(x+y)令x+y=a,x-y=b∴(33a+56b)/(56a-33b)=-a/b∴33ab+56b2=-56a2+33ab∴a2+b2=0∴(x+y)2+(x-y)2=0∴x2+y2=0依题意,x2+y2≠0∴此方程无实数解 |