P= x^3 + mx^2 + 3mx -9
P is dividible by (x-3)
Then (x-3) is one of P's factors, and 3 is one of the roots for P.
==> P(x) = (x-3)*Q(x)
==> P(3) = 0
P(3) = 3^3 + m(3^2) + 3m(3) - 9 = 0
==> 27 + 9m + 9m - 9 = 0
==> 18 + 18m = 0
==> 18m = -18
==> m = -1
We’ll help your grades soar
Start your 48-hour free trial and unlock all the summaries, Q&A, and analyses you need to get better grades now.
- 30,000+ book summaries
- 20% study tools discount
- Ad-free content
- PDF downloads
- 300,000+ answers
- 5-star customer support
Already a member? Log in here.
Are you a teacher? Sign up now