Welcome to Westonci.ca, where you can find answers to all your questions from a community of experienced professionals. Discover the answers you need from a community of experts ready to help you with their knowledge and experience in various fields. Experience the ease of finding precise answers to your questions from a knowledgeable community of experts.
Sagot :
Given:
The expression is:
[tex]2x^3+mx^2+nx+c[/tex]
It leaves the same remainder when divided by x -2 or by x+1.
To prove:
[tex]m+n=-6[/tex]
Solution:
Remainder theorem: If a polynomial P(x) is divided by (x-c), thent he remainder is P(c).
Let the given polynomial is:
[tex]P(x)=2x^3+mx^2+nx+c[/tex]
It leaves the same remainder when divided by x -2 or by x+1. By using remainder theorem, we can say that
[tex]P(2)=P(-1)[/tex] ...(i)
Substituting [tex]x=-1[/tex] in the given polynomial.
[tex]P(-1)=2(-1)^3+m(-1)^2+n(-1)+c[/tex]
[tex]P(-1)=-2+m-n+c[/tex]
Substituting [tex]x=2[/tex] in the given polynomial.
[tex]P(2)=2(2)^3+m(2)^2+n(2)+c[/tex]
[tex]P(2)=2(8)+m(4)+2n+c[/tex]
[tex]P(2)=16+4m+2n+c[/tex]
Now, substitute the values of P(2) and P(-1) in (i), we get
[tex]16+4m+2n+c=-2+m-n+c[/tex]
[tex]16+4m+2n+c+2-m+n-c=0[/tex]
[tex]18+3m+3n=0[/tex]
[tex]3m+3n=-18[/tex]
Divide both sides by 3.
[tex]\dfrac{3m+3n}{3}=\dfrac{-18}{3}[/tex]
[tex]m+n=-6[/tex]
Hence proved.
Visit us again for up-to-date and reliable answers. We're always ready to assist you with your informational needs. We hope you found this helpful. Feel free to come back anytime for more accurate answers and updated information. Thank you for trusting Westonci.ca. Don't forget to revisit us for more accurate and insightful answers.
