Update educational notebooks

Author: marcos-dv

authors/marcos-dv/educational/Employee_Scheduling.ipynb

@@ -49,9 +49,6 @@
         "\n",
         "A small business requires different numbers of full-time employees on different days of the week. The company implements a flexible working policy, which states that each full-time employee can work any five days and take two days off in a week. For example, an employee can work on Monday to Thursday and Saturday while taking Friday and Sunday off. The company wants to meet its daily requirements using only full-time employees. The employees are paid \\$200 pay day if they work on regular weekdays while receive an additional \\$100 per day if they work over the weekend. The company's objective is to minimize its payroll expenses.\n",
         "\n",
-        "<div>\n",
-        "    <img src=\"https://raw.githubusercontent.com/ampl/colab.ampl.com/master/authors/marcos-dv/educational/imgs/scheduling.jpeg\" width=\"600\"/>\n",
-        "</div>\n",
         "\n",
         "\n",
         "The following table lists the staffing requirements on each day of the week.\n",

authors/marcos-dv/educational/NFL_Team_Rating.ipynb

@@ -47,8 +47,6 @@
         "---\n",
         "## Problem Description\n",
         "\n",
-        "![picture](https://drive.google.com/uc?id=1zpCeYLlNZePdlL_S9mi9nlrkUSWYticg)\n",
-        "\n",
         "We consider the NFL games from 32 teams. The teams are indexed 1 to 32, for example, team 1 is Arizon, team 2 is Atlanta, and so on.\n",
         "\n",
         "|\tTeam Number\t|\tTeam name\t|\tTeam Number\t|\tTeam name\t|\n",