Given two points (x₁,y₁) and (x₂,y₂) the slope of a trend line that passes through these points would be:
m=(y₂-y₁)/(x₂-x₁) or m=(y₁-y₂)/(x₁-x₂); the result would be the same.
In this case:
(5,80)
(7,65)
m=(65-80)/(7-5)=-15/2
Answer: the slope would be -15/2
