J.R. S. answered 11/23/20
Ph.D. University Professor with 10+ years Tutoring Experience
You neglected to mention what the plot was, or what the x and y axes were. I'll assume it was an Arrhenius plot of ln k vs 1/T according to the linear equation ln k = -Ea/R(1/T) + ln A in the form of y = ax + b.
a = slope = -Ea/R = -1449 where R = 8.314 J/mol-K
-Ea = (8.314)(-1449)
Ea = 12,047 but since you gave no units for the slope or the experiment in general, I can't assign units to this except that it is generally given in joules/mole