Right now seth's age is 4/5 the age of his brother eric. twenty-one years ago, eric was twice as old as seth. what are their ages now?

In the diagram of circle a what is m

Can someone me with this problem . show your work .

Carley bought a jacket that was discounted 10% off the original price. the expression below represents the discounted price in dollars, based on x, the original price of the jacket.