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C2 Exam Question

Hi All,

Would anyone be able to help me with this C2, June 2015 Question please?

3. f(x)= 6X (Cb.) + 3X (Sq.) + Ax + B.

Given that when f(x) is divided by (x+1) the remainder is 45,

a. Show that B - A = 48. (2 Marks)

I was able to do this question.


Given also that (2x + 1) is a factor of f(x),

b. Find the value of A and the value of B. (4 Marks)

If possible could somebody help me with question b please.

Many Thanks
Original post by AgonizedGod
Hi All,

Would anyone be able to help me with this C2, June 2015 Question please?

3. f(x)= 6X (Cb.) + 3X (Sq.) + Ax + B.

Given that when f(x) is divided by (x+1) the remainder is 45,

a. Show that B - A = 48. (2 Marks)

I was able to do this question.


Given also that (2x + 1) is a factor of f(x),

b. Find the value of A and the value of B. (4 Marks)

If possible could somebody help me with question b please.

Many Thanks


What have you tried for part b? :h:
Reply 2
If (2x+1) is a factor of f(x) then f(-1/2)=0.
Do the same thing you do for the first part of the question to find an equation in terms of a and b.
Then it's just normal simultaneous equation to find a and b and hence f(x).
Reply 3
Original post by SeanFM
What have you tried for part b? :h:


Original post by B_9710
If (2x+1) is a factor of f(x) then f(-1/2)=0.
Do the same thing you do for the first part of the question to find an equation in terms of a and b.
Then it's just normal simultaneous equation to find a and b and hence f(x).


I've gotten to the point myself where I managed to get: -1/2A + B = 0 and the B - A = 48 from part a. Am I right in assuming that I need to use these for my simultaneous equations?
Original post by AgonizedGod
I've gotten to the point myself where I managed to get: -1/2A + B = 0 and the B - A = 48 from part a. Am I right in assuming that I need to use these for my simultaneous equations?


Correct. :borat:
Reply 5
Thanks for the help both of you, I was able to get a final answer of A= -96 and B= -48

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