koordinat titik balik grafik fungsi kuadrat f(x) = -x²+4x+5 adalah.... a. (-9,2) b. (-2,-9) c. (-2,9) d. (2,9) e. (2,-9)

Kelas 10 Matematika
Bab Fungsi Kuadrat

f(x) = -x² + 4x + 5
a = -1; b = 4; c = 5

Sumbu simetri
= -b/2a
= - 4/(2 . -1)
= 2

f(2) = - (2²) + 4 . 2 + 5
f(2) = -4 + 8 + 5
f(2) = 9

(2, 9)