Question

a+b/c=11 b+a/c=14 (a+b)/c=?

Answer 1

c视为常量,相加减 (a+b)+(a+b)/c=25,(a+b)=25c/(c+1)

(b-a)-(b-a)/c=3 ,(b-a)=3c/(c-1)

两式相加b=(14c^2-11c)/(c^2-1)

两式相减a=(11c^2-14c)/(c^2-1)

所以(a+b)/c=25/(1+c),结果随c变化(c不等于1,-1)