Is there a question...or...?
Because there both addition
The y intercept (b) = 4 and the slope (m) is 12
y = mx + b so its:-
y = 12x + 4
X+(x-5) +(x-10) ...
This adds up to 8x -140 seconds where x is the 1st race time.
This adds up to 44:20 minutes
44mins * 60 sec/min = 2640 seconds + 20 = 2660 seconds cummulative
8x - 140 = 2660 8x =2800 sec
8x = 350 seconds or 4.5mins for the 1st race
Race 2: subtract 5 seconds yields 4 mins 25 seconds