Dejah is proving that perpendicular lines have slopes that are opposite reciprocals. She draws line s and labels two points on the line as (−a, 0) and (0, b). Enter the answers, in simplest form, in the boxes to complete the proof.

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?