# function min and vertex

• May 8th 2012, 01:32 PM
jonathanraxa
function min and vertex
The function f(x) = x^2 - 18x + 83 achieves its minimum at (9,2). If g(x) = f(x-4)-3, where is the vertex of g(x)?

Thanks
• May 8th 2012, 01:48 PM
emakarov
Re: function min and vertex
What do you know about how the operations \$\displaystyle f(x)\mapsto f(x+c)\$ and \$\displaystyle f(x)\mapsto f(x)+x\$ change the graph of f(x)? What are your difficulties in applying this knowledge to this problem?
• May 8th 2012, 02:02 PM
jonathanraxa
Re: function min and vertex
I'm not sure if I'm understanding the problem correctly. I know there's a way of getting the vertex, but I'm just not sure whether or not I'm missing something else.
• May 8th 2012, 02:12 PM
emakarov
Re: function min and vertex
Quote:

Originally Posted by jonathanraxa
I'm not sure if I'm understanding the problem correctly. I know there's a way of getting the vertex, but I'm just not sure whether or not I'm missing something else.

Well, all the problem is asking is to find the vertex of g(x). If you don't understand a particular phrase or word or if you see alternative readings of the problem, feel free to ask about them. Also, feel free to to post your solution to be checked.
• May 9th 2012, 10:46 AM
HallsofIvy
Re: function min and vertex
You are told where the vertex of y= f(x) is. Whoever assigned this problem expects you to know that replacing "x" with "x- a" shifts the graph right "a" places and adding "b" to the end of the function (g(x)= f(x)+ b) moves the graph up "b" places.
• May 9th 2012, 10:44 PM
Chuka
Re: function min and vertex
Quote:

Originally Posted by jonathanraxa
The function f(x) = x^2 - 18x + 83 achieves its minimum at (9,2). If g(x) = f(x-4)-3, where is the vertex of g(x)?

Thanks

Lol, are you in Kelly's class? Yea i need help on this question too, I only have 1 more chance. Is the answer (5,-3)?
• May 10th 2012, 02:35 AM
emakarov
Re: function min and vertex
Quote:

Originally Posted by Chuka