Find the product of 20 x 9 x 5 tell which property you used

How do you use the elimination method for this question? explain, because i really want to understand!

Tabby sells clothing at a retail store, and she earns a commission of 6.25% on all items she sells. last week she sold a pair of jeans for $32.50, a skirt for $18.95, and 2 blouses for $14.95 each. what was tabby's total commission? a $4.15 b $5.08 c $81.35 d $348.60

What is the equation of a line passing through (-6,5) and having a slope of 1/3