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#1 2012-10-19 04:03:33
- danthemaths
- Novice
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The Remainder Theorem
hey guys, I am stuck on this question:
"The Remainder when x^3-2x^2+ax+5 is divided by x-3 is twice the remainder when the same expression is divided by x+1. Find the value of the constant a."
I know the answer is 4 but i dont know how to get there.
I have started it off but dont know what to from then on...
I worked out f(3) to be -14=3a
...and f(-1) to be a=2
Am I on the right lines? and what do I do from then on? this will really help me out
thanks in advance
danthemaths
#2 2012-10-19 04:55:39
- bob bundy
- Moderator
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Re: The Remainder Theorem
hi danthemaths
Welcome to the forum.
Am I on the right lines?
Not quite.
When you put x = 3 you get a remainder. Let's say
and when x =-1
You are also told that
So make an equation from this and solve for a.
Hope that helps.
?? But I'm not getting a = 4 ??
Bob
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei