\[2c(3c - 7) - (c - 1)(c + 4) =\]
\[= 6c^{2} - 14c - \left( c^{2} - c + 4c - 4 \right) =\]
\[= 6c^{2} - 14c - c^{2} - 3c + 4 =\]
\[= 5c^{2} - 17c + 4.\]