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2013-10-16T23:35:29-03:00
(x) = ax² + bx + c

f(0) = 5 --> c = 5
f(2) = -3 --> 4a + 2b +5 = -3
f(3) = -4 --> 9a + 3b +5 = -4

4a + 2b = -8
9a + 3b = -9 
12a + 6b = -24
18a + 6b = -18
6a = 6
a = 1
4 + 2b = -8
2b = -12
b = -6

f(x) = x² - 6x + 5

Δ² = 36 - 20 = 16

vértice
Vx = -b/2a = 6/2 = 3
Vy = -Δ²/4a = -16/4 = -4 

Vx + Vy = 3 - 4 = -1 
2 5 2