AHSME 1975 Problem 2

For which real values of m are the simultaneous equations \begin{align*}y &= mx + 3 \ y& = (2m - 1)x + 4\end{align*} satisfied by at least one pair of real numbers $(x,y)$? $\textbf{(A)}\ \text{all }m \textbf{(B)}\ \text{all }m\neq 0 \textbf{(C)}\ \text{all }m\neq 1/2 \textbf{(D)}\ \text{all }m\neq 1 \textbf{(E)}\ \text{no values of }m$