Question

Of the five quadratics listed below, four of them have two distinct roots. The fifth quadratic has a repeated root. Find the value of the repeated root.

-x^2 + 18x + 81
3x^2 - 3x - 168
x^2 - 4x - 4
25x^2 - 30x + 9
x^2 - 14x + 24

Answer 1

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