Answer:
a ^ 2 - b ^ 2 = ( a + b ) ( a - b ) where a = 4p and b = 3q.
( 4p + 3q ) ( 4p - 3q )

the penalty he'll incurred into, since July 6 is after the deadline of April 15, is I = Prt
now "t" is in years, how many days after April 15 to July 6? well, 15 + 31 + 30 +6, to convert to years, divide by 365