# Find the function

• September 22nd 2008, 05:12 PM
n8thatsme
Find the function
Find the function of the form $f(x) = Ca^x$. In the graph, m = 3 and q = 27.

m is the x-intercept and q is a point on the graph (-1, 27)

So what is $f(x)$?
• September 22nd 2008, 05:17 PM
Jhevon
Quote:

Originally Posted by n8thatsme
Find the function of the form $f (x) = Cax$. In the graph, m = 3 and q = 27.

m is the x-intercept and q is a point on the graph (-1, 27)

So what is $f(x)$?

there is no need for all this weird formating. it only serves to confuse people. do you mean

$f(x) = CAx$ where $C$ and $A$ are constants?

note that the x-intercept is the x-value when y = 0, so that

$CAm = 0$ ...........................(1)

also, $(-1,27)$ means, when x = -1, y = 27, so that

$CA(-1) = 27$ ..........................(2)

there seems to be some info missing, because this system is inconsistent
• September 22nd 2008, 05:25 PM
Jhevon
Quote:

Originally Posted by n8thatsme
Find the function of the form $f(x) = Ca^x$. In the graph, m = 3 and q = 27.

m is the x-intercept and q is a point on the graph (-1, 27)

So what is $f(x)$?

ok, that's better.

note that you have

f(3) = 0

and

f(-1) = 27

thus you have a pair of simultaneous equations with two unknowns. you can solve for a and c
• September 22nd 2008, 05:26 PM
n8thatsme
I edited the formatting a little bit. I have a graph but I don't know how to show it on here. The graph is the reflection of a^x. But what I gave is my entire problem.