Solution 3.1:1b

When we remove the parentheses, the terms inside change sign:

\displaystyle 3i-(2-i)=3i-2+i.

Then, we collect together real and imaginary parts:

\displaystyle \begin{align}3i-2+i&=-2+(3i+i)\\ &=-2+(3+1)i\\ &=-2+4i\end{align}