hello
his gross income was = $82,969
commission = 4 1/2% or 4.5%
since we have the gross income, we can use that data to find his actual salary for the month.
all we need to do is find 4.5% of 82969 and subtract the value from it

the commission pay was $3733.605
to find his actual salary, subtract 3733.605 from 82969

from the calculations above, his income for last month was $79235.395