Question

Dada a função F(x)= x²-5x+4, calcule:
F(-√5/5)

Answer 1

$F ( \frac{ \sqrt{5} }{5} ) = (\frac{ \sqrt{5} }{5})^{2} -5.\frac{ \sqrt{5} }{5} + 4 \\ \\ \frac{5}{25}- \sqrt{5} +4 \\ \\ \frac{1}{5} - \sqrt{5} +4 \\ \\ \frac{1-5 \sqrt{5} +20}{5} \\ \\ \frac{21-5 \sqrt{5}}{5}$