Row 2 : 8, 10 row 3 : 15, 17, 19 row 4 : 24, 26, 28, 30 row 5 : 35, 37, 39, 41, 43 a. what is the difference between the last number in row 6 and the first number in row 6? show or explain your work. b. write an equation that can be used to find d, the difference between the last number and the first number, for any row r. show or explain your work.