Question

For the graph of f(x)= -3+20x-5x2, what is the x coordinate of its vertex?

Pleassee hellppp!!

Answer 1

have you done derivative yet? That would be extremely easy and conceptually easier to understand.
If you haven't, then put that equation into this form with the decreasing order
f(x) = ax+ bx + c

your vertex would have the x-coordinate at (-b/2a). Good luck! To find y, plug in your numerical x-vertex and solve the function

Answer 2

ax^2+bx+c*
sorry for the typo

Answer 3

Would you PLEASE be able to do it for me? Pleasee im in a hurry, i have a teacher meeting soon!

Answer 4

f(x)= -3+20x-5x2
x= 2. Plug in formula with a = -5, b = 20

Answer 5

where do i put the a and b?

Answer 6

(-b/2a)= vertex
(-20/-10) = 2.
x= 2

Answer 7

Ruka: How do i put the numbers in there? && how do i find them?

Answer 8

2
x=2

Answer 9

vertix is (2,17)

Answer 10

Your former "b" value, in order to became your h value must be divided by 2 and squared.

Answer 11

ok, so after i do what you put in your previous previous answer, how is it written? Caz i dont know how to multyply what by wat and then how its written.. sorry if its too much..

Answer 12

I know that the answer it 2 but i need to show my work on how i found that.

Answer 13

so, this is what i have written down on what you told me so far.
f(x)=-3+20x-5x2
f(x)=-5x2+20x-3
-5x2+20x-3
-5(x2-4x)-3
-4/2=-2 = -22 (the second 2 is supposed to be on top of the first 2) =4
-5(x2-4x+4)-3+y
-5(x2)2-3-20
-5(x-2)2-23

If i did it wrong can you rewrite all that correctly for me to see?