Arecent visit to the hair salon cost brenda $130. she added a 15 percent tip to her bill. what is the amount of the tip?

15% / 100 = 0.15. 15% = 0.15 in decimal form.
Now, all you need to do is multiply $130 by the decimal form of the percentage.
$130 * 0.15 = $19.50. Here tip was $19.50. Always remember that you can divide the percentage by 100 to find its decimal form.

A= b/2 because u simplying both sides of equation