David Gwyn J. answered 10/21/20
Highly Experienced Tutor (Oxbridge graduate and former tech CEO)
The gradient of a line is the change in y divided by the change in x.
The change in y is 2 (8-6) for a change in x of 0 (-5 - -5). Hence the gradient is 2/0 = infinity (or undefined) which means the line is vertical.
Your line equation is x = -5