2c(3c-7)-(c-1)(c+4)

To simplify the expression \( 2c(3c - 7) - (c - 1)(c + 4) \), let's follow the steps:

1. Distribute \( 2c \) in the first term:

\[ 2c(3c) - 2c(7) = 6c^2 - 14c \]

2. Now, distribute in the second term \( (c - 1)(c + 4) \):

\[ c(c) + c(4) - 1(c) - 1(4) = c^2 + 4c - c - 4 = c^2 + 3c - 4 \]

3. Now, substitute back into the expression:

\[ 6c^2 - 14c - (c^2 + 3c - 4) \]

4. Distributing the negative sign:

\[ 6c^2 - 14c - c^2 - 3c + 4 \]

5. Combine like terms:

\[ (6c^2 - c^2) + (-14c - 3c) + 4 = 5c^2 - 17c + 4 \]

So, the simplified expression is:

\[ \boxed{5c^2 - 17c + 4} \]