What are the soultion(s) to the quadratic equation 40- x^2=0

Answer! if you don’t mind, can you explain

Using pert, adam munson was able to determine that the expected project completion time for the construction of a pleasure yacht is 21 months, and the project variance is 4. a) what is the probability that the project will be completed in 17 months? b) what is the probability that the project will be completed in 20 months? c) what is the probability that the project will be completed in 23 months? d) what is the probability that the project will be completed in 25 months? e) what is the due date that yields a 95% chance of completion?

This summer the number of tourists in salem increased 4.5% from last years total of 426000. how many more tourists came to salem this summer