actor a is charging 250+50x where x=number of days actor b is charging 200+60x (guessing that you meant to put + because a - sign wouldn't make sense)
so when are they equal? set them equal to each other 250+50x=200+60x subtract 50x from both sides 250=200+10x subtract 200 from both sides 50=10x divide both sides by 10 5=x