Odpowiedź:
C.
Szczegółowe wyjaśnienie:
A, B i D wykluczam, bo a < 0
[tex]C.\\ f(x) = -(x-2\frac{1}{2})^{2}+12\frac{1}{4} = -(x-\frac{5}{2})^{2}+\frac{49}{4} = -[x^{2}-2\cdot\frac{5}{2}x +(\frac{5}{2})^{2}]+\frac{49}{4}=\\\\=-(x^{2}-5x+\frac{25}{4})+\frac{49}{4} =-x^{2}+5x-\frac{25}{4}+\frac{49}{4}=-x^{2}+5x +\frac{24}{4}\\\\\underline{f(x) = -x^{2}+5x+6}[/tex]
