Variation of $K_{e q}$ with temperature $T$ is given by van't-Hoff equation.
$\log K_{ eq }=-\frac{\Delta H ^{\circ}}{2.303\, RT }+\frac{\Delta S^{\circ}}{ R }$
Slope of the given line is positive indicating that term $A$ is positive thus $\Delta H^{\circ}$ is negative.
Thus. reaction is exothermic.
