Does this picture represent a physical or a chemical change?

What is the solution to the system of equations? (–2, –8) (–1, –5) (0, –2) (2, 4)

Scrub a dub toothbrushes are $4.00 each. there is a 10% discount, but there is also a 6% sales tax after the discount is applied. what is the new price after tax? round to the nearest penny

Alice is paying her bill at a restaurant. but tax on the cost of a male is 5%. she decides to leave a tip 20% of the cost of the meal plus the tax