What does y=mx+c (y, m, x, c)means in this table.thanks

Square # Full, Expanded Expression Simplifie # Grains rice on square Expression 19 n 1 1 2 1+50 1 +50 51 3 1 + 50 + 50 1 + 50(2) 101 4 1 + 50 + 50 +50 1+50(3) 151 5 1 + 50 +50 + 50 +50 1 + 50(4) 201 1+ 50 + 50 + 50 + 50 + 50 1 + 50(5) 251 1 + 50 + 50 + 50 + 50 + 50 +50 1 + 50(6) 301 8 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 1 + 50(7) 351 9 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 1 +50(8) 401 10 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 1 + 50(9) 451 11 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 1 + 50(10) 501 12 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 1 + 50(11) 551 13 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 +50 1 + 50(12) 601 14 1 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 50 + 1 + 50(13) 651 50 19 1 + 50 + 50 + 50 + 50 + 50 +50 + 50 + 50 + 50 + 50 + 50 +50 + 1 + 50(14) 701 50+ 50 2.5 marks b) Using the standard form of a linear equation: y=mx +c Assign values for the variables in the equation, relevant to this different version of the rice and chessboard story: -what does this variable represent in the context of this new version of the story (use the assigned variables from the table above, rather than the ones in the standard from of a linear equation)