Let f(x)=ax7+bx3+cx−5. If f(−7)=7 then find f(7).
f(-7) =
a(-7)^7 + b(-7)^3 + c(-7) - 5 = 7
a(-1)^7 * (7)^7 + b (-1)^3 * (7)^3 + c (-1)(7) - 5 = 7
-a(7)^7 - b (7)^3 - c (7) - 5 = 7
- ( a(7)^7 + b (7)^3 + c(7) ) = 12
a(7)^7 + b(7)^3 + c(7) = -12
So
a(7)^7 + b(7)^3 + c(7) - 5 = -12 - 5
f (7) = -17