Given curves are y2 = 9x and y = 3x
solving the two equations we have
\[\begin{array}{*{35}{l}}
{{\left( 3x \right)}^{2}}~=\text{ }9x \\
9{{x}^{2}}~=\text{ }9x \\
9{{x}^{2}}~\text{ }-9x\text{ }=\text{ }0\text{ }\Rightarrow \text{ }9x\left( x\text{ }-\text{ }1 \right)\text{ }=\text{ }0 \\
\end{array}\]
Thus, x = 0, 1
So, the area of the shaded region is given by
= ar(region OAB) – ar (Δ OAB)
Therefore, the required area is ½ sq.units.