If f(x)  is an even function defined on (−5, 5)  , then the sum of the squares of all numbers satisfying the equation f(x)=f(x+1x+2)  is

f(x) is even function ⇒f(x)=f(−x)  ⇒    f (x+1x+2) =f(x)  =f-x⇒ x+1x+2=x or -x⇒   x2+x−1=0  or   x2+3x+1=0Roots are =−1±52, −3±52   (  all the 4 roots ∈ -5,5 )∴            Sum of their squares=2(1+54 )+2(9+54)=10