The sum of 3 integers is 189. The 1st integer is 28 less than the 2nd. The 2nd integer is 21 less than the sum of the 1st and third integers. What are the three integers?

Math it's appreciated. (picture provided)

What is the missing statement in step 4? ? rts ? ? vtu and ? rtu ? ? vts ? rts ? ? rvs and ? rtu ? ? stv ? vrs ? ? vru and ? usr ? ? usv ? vur ? ? vus and ? uvs ? ? sru

Atown has a population of 12000 and grows at 3.5% every year. what will be the population after 7 years, to the nearest whole number?