Answer
Not invertible.
Work Step by Step
We know that if the determinant of a matrix $\begin{bmatrix}
a &b \\
c & d
\end{bmatrix}$ $, D=ad-bc$ is $0$, then the matrix is not invertible.
Here $D=3\cdot8-4\cdot6=24-24=0$, thus the matrix is not invertible.