If distance between the points (a,2,1) and (1,-1,1) is 5 units ,find a - Maths - Introduction to Three Dimensional Geometry

Question

If distance between the points (a,2,1) and (1,-1,1) is 5 units
,find a

Abhishek Chaudhary · Accepted Answer

(a-1)2 + (2+1)2 + (1-1)2 =
52
a2 + 1 - 2a + 9 = 25
a2 - 2a - 15 = 0
a = -3 or 5

If distance between the points (a,2,1) and (1,-1,1) is 5 units ,find a.