A salesperson at a jewelry store earns 4% commission each week. Last week, Heidi sold $680 worth of jewelry. How much did she make in commission? How much did the jewelry store make from her sales?

Complete the solution of the equation. find the value of y when x equals -5. -4x - 8y = -52

Use sigma notation to represent the following series for 9 terms.

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.