Answer
$\{0,\frac{1}{81}\}$
Work Step by Step
Step 1. Given the equation as $3(x)^{3/4}=(x)^{1/2}$
Step 2. Raise both sides to the 4th power to get: $81(x)^3=x^2$ or $81x^3-x^2=0$ which gives $x=0,\frac{1}{81}$
Step 3. Check answers in the original equation: $\{0,\frac{1}{81}\}$ fit.