{18-12+8-16/3+...} find the sum

Each cookie sells for $0.50 sam spent $90 on baking supplies and each cookie cost $0.25 to make how many cookies does sam need to sell before making a profit formula: sales> cost

What is always true about a positive integer raised to a negative odd power?

In the diagram, ab is tangent to c, ab = 4 inches, and ad = 2 inches. find the radius of the circle.