Questions in the pictures

Find the value of x for which line a is parallel to line b

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?

What is the approximate value of  x  in the equation below.–3.396–0.7080.3040.955