A manager surveyed a random sample of people exiting a movie theater about their use of streaming movies.

The answer is 3(x+5)^2

Factor out 3 from the original equation

3(x^2+10x+25)

Then find two numbers that multiply to give 25 and add to give 10. The two numbers are 5 and 5

This gives...
3(x^2+5x+5x+25)

Factorise the expression in the brackets

3(x+5)(x+5)

Combine like terms

3(x+5)^2