I hope it helps you get it right
4x + 1 = -3
"The product" is the term used to describe the answer of a multiplication equation.
"increased by" means you're adding.
"a number" refers to a variable.
If you want to the know the total price of the jeans, with discount coupon and sales tax then it's $15.76
$75 x 0.30 = $22.50
$22.50 - $10 = $12.50
$12.50 + $3.26 = $15.76