Could someone please explain how to solve/complete an inequality for a graph- more specifically this graph?

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

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.

You receive 15% of the profit from a car wash how much money do you receive from a profit of 300