Math Help - coordinate geometry

1. coordinate geometry

If X(-2,3) and Y(a,-1) are 6 units apart, find the value of a.

2. Originally Posted by positiveion
If X(-2,3) and Y(a,-1) are 6 units apart, find the value of a.
Substitute into the formula for the distance between two points: $\sqrt{(-2 - a)^2 + (3 - [-1])^2} = 6$.

Simplify and then solve for $a$.