Thread: Find a for f(x+6)=2x+a where f(a)=20

I haven't a clue about how to do this. Its my last question and I've been looking at it for almost a half hour now with no result. Any help appreciated...thanks!

Originally Posted by GeeDee

I haven't a clue about how to do this. Its my last question and I've been looking at it for almost a half hour now with no result. Any help appreciated...thanks!

I think it's

f(x+6)=2x+a

f(x+6)=2(x+6)+20

0=2x+12+20

x=-16

(-16+6)=2(-16)+a

a=22

I just taking a guess here

Thanks....I just actually tried doing that before I read your post. But apparently the answer in the book tells me a=8/3 ?

Originally Posted by GeeDee

I haven't a clue about how to do this. Its my last question and I've been looking at it for almost a half hour now with no result. Any help appreciated...thanks!

If your book told you the answer is a = 8/3, then the book is wrong.

You have

and you want
.

Well, if then

Let so




We want , so








-Dan

Originally Posted by topsquark

If your book told you the answer is a = 8/3, then the book is wrong.

You have

and you want
.

Well, if then

Let so




We want , so








-Dan

i thought as much. i saw no need to introduce a new variable though.



and then, continue as you did

Originally Posted by Jhevon

i thought as much. i saw no need to introduce a new variable though.



and then, continue as you did

I was trying not to confuse the original poster with the "x + 6 - 6" thing. Maybe good, maybe not.

-Dan

Originally Posted by topsquark

I was trying not to confuse the original poster with the "x + 6 - 6" thing. Maybe good, maybe not.

-Dan

yeah, you're right. that maneuver does confuse some people