The $50 off was like a coupon after you brought all your merchandise to the counter, so we have to add it back in to determine the number of shirts.
$400+$50=$450 original price of shirts
Original price ÷ price per shirt= quantity purchased
$450 ÷ $15/shirt= 30 shirts purchased
Allison bought 30 shirts.
Hope this helps! :)
Simplified answer would be 60k^2+k
and you get that answer by combining like terms, Good Luck!
