Which of the following is correct for the vertex of the parabola
f(x) = 2x2 + 8x - 12 ?
A
There is a local minimum at
(-2, -20)
B
There is a local maximum at
(-2, -20)
C
There is a local minimum at
(2, -20)
D
There is a local maximum at
(2, -20)

Question

Which of the following is correct for the vertex of the parabola 
f(x) = 2x2 + 8x - 12 ?
A
There is a local minimum at 
(-2, -20)
B
There is a local maximum at 
(-2, -20)
C
There is a local minimum at 
(2, -20)
D
There is a local maximum at 
(2, -20)

anonymous · Answer

@ganeshie8 
@hartnn

ganeshie8 · Answer

what does the `sign of leading coefficient` tell you about the end behavior of a polynomial ?

anonymous · Answer

.....idk

ganeshie8 · Answer

Okay, we can use the sign of leading coefficient to figure out whether the parabola opens up or down

anonymous · Answer

i want a medal tho... .-.

anonymous · Answer

i probably don't know the answer anyways but ill try

ganeshie8 · Answer

$$f(x) = \color{red}{2x^2} + 8x - 12$$
$ \color{red}{2x^2} $ is called leading term
and its coefficient $\color{red}{2}$ is called leading coefficient

anonymous · Answer

i think its c but im not sure

ganeshie8 · Answer

Since the leading coefficient is positive, the function increases for large positive and negative values of $x$. The graph looks something like below :

|dw:1418567754421:dw|

ganeshie8 · Answer

In light of above info, see if you can eliminate any options ?

anonymous · Answer

cant understand

ganeshie8 · Answer

can you pinpoint which part you cant understand ?

anonymous · Answer

The whole thing

ganeshie8 · Answer

see if this video helps https://www.khanacademy.org/math/algebra/quadratics/solving_graphing_quadratics/v/quadratic-functions-2

anonymous · Answer

ok