Write an algebraic expression that is equivalent to the expression cot(arctan x)

How can the correlation in the scatter plot graph below best be described? positive correlation negative correlation both positive and negative no correlation

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?

In the diagram of circle o, what is the measure of zabc?