$EI \, t_{A/B} = (Area_{AB}) \, \bar{X}_A$
$EI \, t_{A/B} = \frac{1}{2}(2)(1200)(\frac{4}{3}) - 600(1)(\frac{3}{2}) - \frac{1}{2}(1)(600)(\frac{5}{3})$
$EI \, t_{A/B} = 200 \, \text{ N}\cdot\text{m}^3$
$EI \, \delta = \frac{1}{2}(EI \, t_{A/B})$
$EI \, \delta = \frac{1}{2}(200)$
$EI \, \delta = 100 \, \text{ N}\cdot\text{m}^3$ answer