mohon bantuannya dong..

tampak gambar
kurva melalui (0,0) dan titik puncak (p,q) = (2,2)
y - q  = a(x -p)²  --> y  = a(x - 2)² + 2
melalui (0,0) --> 0 = a(-2)² + 4
4a + 4 = 0
4a = - 4
a = - 1

pers kurva  y - q = a(x -p)² 
y - 2 = -1(x - 2)²
y = -(x² - 4x + 4) + 2
y = - x² + 4x  - 4 + 2
y = - x² + 4x - 2
f(x)= - x² + 4x - 2