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C2 help

I thought i knew how to do this, but somewhere solution bank chaged a number and im not sure why:
f(x)=x^3+ax+b
when it's divided by (x-4) the remainder is 32
when its divided by (X+2) the remainder is -10
Find a and b
Original post by vishnarliee
I thought i knew how to do this, but somewhere solution bank chaged a number and im not sure why:
f(x)=x^3+ax+b
when it's divided by (x-4) the remainder is 32
when its divided by (X+2) the remainder is -10
Find a and b


What have you tried? :h:
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vishnarliee
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Original post by SeanFM
What have you tried? :h:

I used the factor therom, and i solved simultaneously, for the first equation i got '4a+b=-32', which is right according to solution bank. for the second i got '-2a+b=-2', but according to solution bank it should be equal to 40?
Original post by vishnarliee
I used the factor therom, and i solved simultaneously, for the first equation i got '4a+b=-32', which is right according to solution bank. for the second i got '-2a+b=-2', but according to solution bank it should be equal to 40?


Okay, what did you do to get that second equation then?

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