1
                                                                    EXHIBIT 3.31



                                                            STATE OF DELAWARE
                                                           SECRETARY OF STATE
                                                        DIVISION OF CORPORATIONS
                                                        FILED 4:30 PM 10/19/1999
                                                          991442830 - 3088780



                              CERTIFICATE OF MERGER
                                       OF
                    PEGASUS BROADCASTING OF SAN JUAN, L.L.C.
                                      INTO
                      LIN TELEVISION OF PUERTO RICO, L.L.C.


                  Pursuant to Section 18-209 of the Delaware Limited Liability
Company Act, the undersigned surviving limited liability company, LIN Television
of Puerto Rico, L.L.C. (the "Company") submits the following Certificate of
Merger for filing and certifies that:

                  1. The name and jurisdiction of formation of each of the
limited liability companies which is to merge are:

<Table>
<Caption>
                         Name                                       Jurisdiction
        -------------------------------------                       ------------
                                                                 
        LIN Television of Puerto Rico, L.L.C.                         Delaware

        Pegasus Broadcasting of San Juan, L.L.C.                      Delaware
</Table>

                  2. An agreement of merger has been approved and executed by
each of the limited liability companies set forth in Paragraph 1 hereof.

                  3. The name of the surviving limited liability company is: LIN
Television of Puerto Rico, L.L.C.

                  4. The merger shall become effective upon the filing of this
Certificate of Merger.

                  5. The agreement of merger is on file at a place of business
of the Company, which is located at Four Richmond Square, Providence, RI 02906.

                  6. A copy of the agreement of merger will be furnished by the
Company, on request and without cost, to any member of any domestic limited
liability company or any person holding an interest in any other business entity
which is to merge.


   2






                  IN WITNESS WHEREOF, this Certificate of Merger has been duly
executed as of the 19th day of October, 1999, and is being filed in accordance
with Section 18-209 of the Act by an authorized person of the surviving company
in the merger.


                                        LIN TELEVISION OF PUERTO
                                        RICO, LLC

                                        BY: LIN TELEVISION CORPORATION



                                        /s/ DENISE M. PARENT
                                        ----------------------------------------
                                          By:  Denise M. Parent
                                          Title: VP -- Deputy General Counsel








                                      -2-









   3

                                                            STATE OF DELAWARE
                                                           SECRETARY OF STATE
                                                        DIVISION OF CORPORATIONS
                                                       FILED 11:00 AM 10/20/1999
                                                          991443146 - 3088780


                            CERTIFICATE OF AMENDMENT

                         TO THE CERTIFICATE OF FORMATION

                                       OF

                       LIN TELEVISION OF PUERTO RICO, LLC


                  This Certificate of Amendment of LIN Television of Puerto
Rico, LLC (the "Company"), dated as of October 20, 1999, is being duly executed
and filed by an authorized person to amend the Certificate of Formation of the
Company in accordance with Section 18-202 of the Delaware Limited Liability
Company Act.

                  FIRST. The name of the Company is LIN Television of Puerto
Rico, LLC.

                  SECOND. The Certificate of Formation of the Company shall be
amended by deleting the name "LIN Television of Puerto Rico, LLC" therefrom and
inserting in lieu thereof Televicentro of Puerto Rico, LLC, which shall
constitute the new name of the Company.

                  IN WITNESS WHEREOF, the undersigned has executed this
Certificate of Amendment to the Certificate of Formation of LIN Television of
Puerto Rico, LLC as of the date first above written.





                                        /s/ DENISE M. PARENT
                                        ----------------------------------------
                                        Denise M. Parent
                                        Authorized Person