[tex]\large\bold{Answer:}[/tex]
Alternate Forms:
[tex]f( \times ) = \frac{ { \times }^{2} }{5}f( \times ) = { \times }^{2} + 4f( \times ) = - 1 \\ [/tex]
[tex] { \times }^{2} = 5f( \times ) { \times }^{2} + 4 = f( \times )f( \times ) + 1 = 0 \\ [/tex]
