Function question

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• Apr 26th 2007, 12:14 PM
Mathfailure
Function question
Hello. I was wondering how I would set this problem up. it reads " Suppose f(x)= (x+6)/(x-4). Find all values of "a" for which f(a)=2.

Thanks for any help!!!

JAson
• Apr 26th 2007, 12:57 PM
Jhevon
Quote:

Originally Posted by Mathfailure
Hello. I was wondering how I would set this problem up. it reads " Suppose f(x)= (x+6)/(x-4). Find all values of "a" for which f(a)=2.

Thanks for any help!!!

JAson

okay, so f(a) just means we plug a into the function, they want the value of the function when a is plugged in to be 2, so

f(a) = (a + 6)/(a - 4) = 2
=> a + 6 = 2(a - 4)
=> a + 6 = 2a - 8
=> a = 14
• Apr 26th 2007, 02:32 PM
Mathfailure
Quote:

Originally Posted by Jhevon
okay, so f(a) just means we plug a into the function, they want the value of the function when a is plugged in to be 2, so

f(a) = (a + 6)/(a - 4) = 2
=> a + 6 = 2(a - 4)
=> a + 6 = 2a - 8
=> a = 14

Hello. Sorry bout the confusion, but how does a+6=2a-8 make a equal to 14? thanks
• Apr 26th 2007, 02:42 PM
topsquark
Quote:

Originally Posted by Mathfailure
Hello. Sorry bout the confusion, but how does a+6=2a-8 make a equal to 14? thanks

Step by step:
a + 6 = 2a - 8

-a + a + 6 = -a + 2a - 8

6 = a - 8

6 + 8 = a - 8 + 8

14 = a

-Dan