I need help with this does anyone know this answer i need help with this???

What is the missing constant term in the perfect square that starts with x^2 -20x

Is a positive integer raised to a negative power always positive

Do some research and find a city that has experienced population growth. determine its population on january 1st of a certain year. write an exponential function to represent the city’s population, y, based on the number of years that pass, x after a period of exponential growth. describe the variables and numbers that you used in your equation.