Question

Dada a função f(t)=6-4t-2t² , podemos afirmar que sua parábola intercepta o eixo das abscissas nas raízes:
a) (3, 2)
b) (-3,1)
c) (3, -2)
d) (-1, 3)
e) (1, -3)

Answer 1

6-4t-2t² = 0. ===> :(-2)

t² +2t -3=0

∆= 4 +12=16 => √∆=4

t' = -b+√∆/2a = -2+4/2= 2/2 = 1 ✓

t'' = -b-√∆/2a = -2-4/2= -6/2= -3 ✓