Concept:
Area between curves:
\[
\int (upper - lower)\,dx
\]
Step 1: Find intersection.
\[
x^{5/2} = x \Rightarrow x=0,1
\]
Step 2: Set integral.
\[
\int_0^1 (x - x^{5/2})dx
\]
Step 3: Evaluate.
\[
= \left[\frac{x^2}{2} - \frac{2}{7}x^{7/2}\right]_0^1
= \frac{1}{2} - \frac{2}{7}
\]
\[
= \frac{7-4}{14} = \frac{3}{14}
\]