Determine the following for the quadratic function f(x) = 2 x^2 + 5 x - 7:

Find the coordinates of the vertex (h,k)

Question

Determine the following for the quadratic function f(x) = 2 x^2 + 5 x - 7:

Find the coordinates of the vertex (h,k)

anonymous · Answer

I already know h, by the way, just not k.

anonymous · Answer

k = f(h)
so u can calculate k

anonymous · Answer

I know. I must have made an arithmetical error. I just can't seem to notice what it is.

anonymous · Answer

here's what I have so far: f(5/4) = 2 (5/4)^2 + 5 (5/4) -7

anonymous · Answer

25/8+25/4-7 = 75/8 -7 = 19/8 (which is apparently wrong)

anonymous · Answer

Can you see any errors within my calculations?

anonymous · Answer

Hi there, qpHalcy0n

anonymous · Answer

Any ideas?

anonymous · Answer

I'm not a calculator, give me a sec ;)

anonymous · Answer

Naturally ;)

anonymous · Answer

i think your calculations are correct

anonymous · Answer

Well, first off, your signs are incorrect. 
h = -b/2a

anonymous · Answer

Um...but the website we use approved of my definition of h.

anonymous · Answer

And...I mean, after all a does equal 2 and b 5, so...why wouldn't -5/4 be correct?

anonymous · Answer

They are incorrect or you wrote the problem down incorrectly. I'm going with the latter.

anonymous · Answer

Oh, wait...nvm

anonymous · Answer

So use -5/4 and see what you get now.

anonymous · Answer

-81/8, which is correct. Thank you for making me aware of my own stupid mistakes!!

anonymous · Answer

No prob.

anonymous · Answer

Have a good day/night!!