Westonci.ca offers quick and accurate answers to your questions. Join our community and get the insights you need today. Join our Q&A platform and get accurate answers to all your questions from professionals across multiple disciplines. Experience the convenience of finding accurate answers to your questions from knowledgeable experts on our platform.

Find the values of a and b given that the polynomial P(x) = x^3+ ax^2 +x+b, is divisible by
both x-1 and x + 3.​

Sagot :

Answer:

a=4

b=-6

Step-by-step explanation:

If P(x) is divisible by x-c, then P(c)=0.

So P(1)=0 implies 1^3+a1^2+1+b=0

and

P(-3)=0 implies (-3)^2+a(-3)^2+-3+b=0

So notice we have a system to solve.

Let's simply it.

First equation:

1^3+a1^2+1+b=0

1+a+1+b=0

2+a+b=0

a+b=-2

Second equation:

(-3)^3+a(-3)^2+-3+b=0

-27+9a-3+b=0

9a+b-30=0

9a+b=30

Let's put our system together:

a+b=-2

9a+b=30

This is setup so if we subtract the equations b will eliminate allowing us to solve for a:

-8a=-32

a=4

If a=4 and a+b=-2, then 4+b=-2 giving us b=-6.

a=4

b=-6