If a circle has a diameter of 10cm what is the radius

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

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?

Which of the following is an example of conditional probability