SOLUTION: Find the value of k if (x-1) is a factor of 4x3+ 3x2-4x +k.

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Question 984481: Find the value of k if (x-1) is a factor of 4x3+ 3x2-4x +k.
Found 2 solutions by srinivas.g, ikleyn:
Answer by srinivas.g(540) About Me  (Show Source):
You can put this solution on YOUR website!
Given Expression f(x) =4x%5E3%2B3x%5E2-4x%2Bk
if (x-1) is factor of above expression
then if we put x=1 in the above expression , then the expression should be 0
hence
4%2A%281%29%5E3%2B3%2A%281%29%5E2-4%2A%281%29%2Bk=0
4%2B3-4%2Bk=0
3%2Bk=0
k= -3
Result : k=-3

Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!

The fact that  x-1  is a factor of  4x%5E3+%2B+3x%5E2+-+4x++%2B+k  means that  1  is the root of this polynomial,  i.e.

4%2A1%5E3+%2B+3%2A1%5E2+-+4%2A1+%2B+k = 0.

It gives you  k = -4 - 3 + 4 = -3.

Answer.  k = -3.