广大附中初一专家讲件例10：设ax+by=7,ax^2+by^2=49,ax^3+by^3=133,ax^4+by^4=406
问题描述：
广大附中初一专家讲件例10：设ax+by=7,ax^2+by^2=49,ax^3+by^3=133,ax^4+by^4=406
试求：1995(x+y)+6xy-(17/2)(a+b)的值
答
ax+by=7,ax^2+by^2=49得:[a = 7*(y-7)/x/(-x+y),b = -7*(x-7)/y/(-x+y)] (1)ax^2+by^2=49,ax^3+by^3=133 得:[a = 7*(7*y-19)/x^2/(-x+y),b = -7*(-19+7*x)/y^2/(-x+y)] (2)ax^3+by^3=133,ax^4+by^4=406 得:[a = 7*(-...