Resposta :
-x² + 4x + 40
∆ = b² - 4ac
∆ = 4² - 4 . (-1) . 40
∆ = 16 + 160
∆ = 176
xv = - b
-----
2a
xv = - 4
---------
2 . (-1)
xv = - 4
------
- 2
xv = 2
yv = - ∆
-------
4a
yv = - 176
-------
4 . (-1)
yv = - 176
-------
- 4
yv = 44
V , F , V
-x² + 4x + 40
∆ = b² - 4ac
∆ = 4² - 4 . (-1) . 40
∆ = 16 + 160
∆ = 176
xv = - b
-----
2a
xv = - 4
---------
2 . (-1)
xv = - 4
------
- 2
xv = 2
yv = - ∆
-------
4a
yv = - 176
-------
4 . (-1)
yv = - 176
-------
- 4
yv = 44
V , F , V