Please help me

Airline passengers arrive randomly and independently at the passenger-screening facility at a major international airport. the mean arrival rate is 10 passengers per minutes. compute the following probabilities. p(x = 4) p(x > 11)

Xto the second power plus 14x plus 48. what are the factors? we are doing factoring trinomials with a=1

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?