Find the standard form of the equation of the circle with center (-2,5) and tangent to the line y=2

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How do you solving the solution of each system using elimination?

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?