find the possible values of a, if the distance between the points is 5, and the coordinates are (1,1) and (4,a)
d^2 = (a-1)^2 + 9 = 25
a^2 -2a + 10 = 25
a^2 - 2a = 15
a^2 - 2a - 15 = 0
a = [ 2 +/- sqrt(64))/2
a = 2+/- 8
a = 10 or -6
a^2 -2a + 10 = 25
a^2 - 2a = 15
a^2 - 2a - 15 = 0
a = [ 2 +/- sqrt(64))/2
a = 2+/- 8
a = 10 or -6