Question

find the value of (a) so that p(x)=x³-ax²-13x+15 is exactly divisible by x-1​

Answer 1

Answer:

Using Factor Theorem.

If p(x) is divisible by x - 1 then

p(-[-1]) = 0

or p(1) = 0.

Substituting x = 1 in p(x) and equating to 0.

1^3 - a(1)^2 - 13(1) + 15 = 0

1 - a - 13 + 15 = 0

3 - a = 0

a = 3.