The population of a city increases by 4,000 people each year. In 2025, the population is projected to be 450,000 people. What is an equation that gives the city's population p (in thousands of people) x years after 2010?

Let x be the number of years after 2010.

The population of the city in 2010 was 0 (since we are counting from 2010).
From 2010 to 2025, which is a span of 15 years, the population increased by 4,000 people per year. So, in x years after 2010, the population increases by 4,000x people.
Therefore, the equation that gives the city's population in thousands of people x years after 2010 is:
p = 4x + 0
Simplifying the equation, we get:
p = 4x