SOLUTION: If f(x-2)=6x-7, what is f(x)? The answer is f(x)=6x+5, but I have no idea how the answer is found! I keep ending up with 6x-17. Here is what I did.... f(x)= 6(x-2)+2-7 f(x

Algebra ->  Rational-functions -> SOLUTION: If f(x-2)=6x-7, what is f(x)? The answer is f(x)=6x+5, but I have no idea how the answer is found! I keep ending up with 6x-17. Here is what I did.... f(x)= 6(x-2)+2-7 f(x      Log On


   



Question 220553: If f(x-2)=6x-7, what is f(x)?
The answer is f(x)=6x+5, but I have no idea how the answer is found! I keep ending up with 6x-17. Here is what I did....
f(x)= 6(x-2)+2-7
f(x)= 6x-12-5
f(x)= 6x-17
Please help! I think you're supposed to add 2 somewhere but I don't know where, why or how!

Found 2 solutions by stanbon, MathTherapy:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If f(x-2)=6x-7, what is f(x)?
The answer is f(x)=6x+5
-----------------------------
The original equation was shifted 2 units to the right to get
f(x-2) = 6x-7
----------------------
So shift it 2 units to the left to get back to f(x)
f(x) = 6(x+2)-7
f(x) = 6x+12-7
f(x) = 6x+5
=======================
Cheers,
Stan H.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
If f(x - 2) = 6x – 7, what is f(x)?

Since we need the right side of the equation in f(x – 2) = 6x - 7 to contain the binomial (x – 2), we have to “fix” it to make it that way.

Since we have 6x – 7 on the right-hand side of the equation, and we need to the binomial (x – 2), we then need to subtract 5, and then add 5 to the right side. In other words,

f(x - 2) = 6x – 7 now becomes: f(x - 2) = 6x – 7 – 5 + 5.

As seen, 5 was subtracted, and then added to the right-side to “adjust” but not change the equation.

Now, f(x - 2) = 6x – 7 – 5 + 5 can be rewritten as: f(x - 2) = 6x – 12 + 5, which can again be rewritten as f(x - 2) = 6(x – 2) + 5.

Now, since f(x - 2) = 6(x – 2) + 5, then f(x) = 6(x) + 5, or: highlight_green%28f%28x%29+=+6x+%2B+5%29

Send comments and “thank yous” to MathMadEzy@aol.com