Does my line have a +ve or –ve gradient

Your $Gradient\ (m)=(y(chang\e\ i\n))/(x(chang\e\ i\n)$

Can have a +ve value or a –ve value, and you only know this if you know where to start.

Start from the left this line has a negative gradient

Start from the left this line has a positive gradient

Always start to measure the change in y and the change in x from the point that is FURTHEST TO THE LEFT.