What number would you add to both sides of x2 + 7x = 4 to complete the square? a.2^2 b.7^2 c, 7^2/2 d.(7/2)^2

Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city. studies on every subject in the population divide a population in groups and obtain a sample studies with a limited amount of time demonstrate existing traits in a population studies with the nth person selected