can someone help me through the process of this question?

VC HOW MANY ADDITIONAL UNITS NEED TO BE SOLD ABOVE 35,300 FOR THE PROPOSAL TO INCREASE ATNI BY $34,692? ANSWER 5,600 ATNI CHANGE = 1-TR((-FIXED COSTS CHANGE) + (CM/UNIT CHANGE X EXISTING UNITS) + (REVISED CM/UNIT X UNIT CHANGE)) PER UNIT TOTAL UNITS = 40,900 SALES 100.00% 55.00 2,249,500 62.45% 34.35 1,404,915 CM 37.55% 20.65 844,585 FC 510,125 100.00% 334,460 TAX 30.00% 100,338 AT 70.00% 234,122 PT VC HOW MANY ADDITIONAL UNITS NEED TO BE SOLD ABOVE 35,300 FOR THE PROPOSAL TO INCREASE ATNI BY $34,692? ANSWER 5,600 ATNI CHANGE = 1-TR((-FIXED COSTS CHANGE) + (CM/UNIT CHANGE X EXISTING UNITS) + (REVISED CM/UNIT X UNIT CHANGE)) PER UNIT TOTAL UNITS = 40,900 SALES 100.00% 55.00 2,249,500 62.45% 34.35 1,404,915 CM 37.55% 20.65 844,585 FC 510,125 100.00% 334,460 TAX 30.00% 100,338 AT 70.00% 234,122 PT