Question

Which of the following is a polynomial with roots negative square root of 5, square root of 5, and 3?

Answer 1

The polynomial with those roots would be: 

y = (x + √5)(x - √5)(x - 3) 
▬▬▬▬▬▬▬▬▬▬▬ multiply this out to get 
y = (x² - 5)(x - 3) 

y = x³ - 3x² - 5x +15