+1911 One of the five quadratics below has a repeated root. (The other four have distinct roots.) What is the repeated root?
-x^2 - 18x + 49
3x^2 - 6x + 48
8x^2 - 32x + 16
25x^2 - 30x + 9
x^2 - 14x + 16
+37144 Repeated root is 3/5 ( or 0.6)
By completing the square:
25 x^2 -30x + 9 =0
25 ( x^2 -1.2x) + 9 = 0
25 (x - .6)^2 - 9 + 9 = 0
25 ( x -.6)^2 = 0 shows two roots at x = 0.6 ( or 3/5)
