Can someone asap! this is the only question i’m struggling with!

How do i do this activity, is appreciated

The jewelry store is having a sale. necklaces that were regularly priced at $23.50 are on sale for $18.80. what is the percentage of decrease in the price of necklaces?

The graph of f(x) is obtained by reflecting the graph of f(x)=-3|x| over the x-axis. which equation describes f(x)? a) f(x)=3|x| b) f(x)=|x+3| c) f(x)=-3|x| d) f(x) = - |x+3|