3 (had to feel the space with words)
486.65 is the answer to the question
Answer: 3/5
Step-by-step explanation: The fourth quadratic in the list is the square of a binomial:
25x^2 - 30x + 9 = (5x - 3)^2
Therefore, the repeated root of this quadratic is the solution to 5x - 3=0, which is 3/5