Answer
Real part= $3$
Imaginary part= $0$
Work Step by Step
A complex number is written as $a+bi$, where $a$ is the real part and $b$ is the imaginary part as it is multiplied to the imaginary unit $i$.
Writing the complex number in the question as $3+0i$, we find that $3$ represents the real part while $0$ represents the imaginary part.