Which statement best describes how to determine whether f(x) = 9 – 4x2 is an odd function? determine whether 9 – 4(–x)2 is equivalent to 9 – 4x2. determine whether 9 – 4(–x2) is equivalent to 9 + 4x2. determine whether 9 – 4(–x)2 is equivalent to –(9 – 4x2). determine whether 9 – 4(–x2) is equivalent to –(9 + 4x2).