The length of the segment between the points $(2a, a-4)$ and $(4, -1)$ is $2\sqrt{10}$ units. What is the product of all possible values for $a$?
+36916 Similar to just posted distance question
Use distance formula
(2a-4)^2 + (a-4 - -1)^2 = (2 sqrt10)^2
4a^2 -16a + 16 + a^2 -6a+9 = 40
5a^2 -22a -15 = 0 Use quadratic formula to find a = 5 or -0.6 (if I made no mistakes!)
