If f(x)=ax7+bx3+cx−5 (a, b, c are real constants) and f−7=7, then the range of f7+17 cosx is
[-34, 0]
[0, 34]
[-34, 34]
{-34, 34}
f(7)+f(−7)=−10 ⇒f(7)=−17
⇒f(7)+17cosx=−17+17cosx which has the range [-34, 0]