Evaluate the summation below. \[ \sum_{m=1}^{7}(-3-3 m) \]

To evaluate the summation \[ \sum_{m=1}^{7}(-3-3 m), \] first, we can factor out the common term in the expression inside the summation. The expression \(-3 - 3m\) can be rewritten as: \[ -3 - 3m = -3(1 + m). \] Thus, we can rewrite the summation as: \[ \sum_{m=1}^{7} (-3(1 + m)) = -3 \sum_{m=1}^{7} (1 + m). \] Next, we need to compute the sum \[ \sum_{m=1}^{7} (1 + m). \] This can be split up into two parts: \[ \sum_{m=1}^{7} (1 + m) = \sum_{m=1}^{7} 1 + \sum_{m=1}^{7} m. \] Calculating the first part: \[ \sum_{m=1}^{7} 1 = 7. \] Calculating the second part, we can use the formula for the sum of the first \(n\) natural numbers, which is: \[ \sum_{m=1}^{n} m = \frac{n(n+1)}{2}. \] For \(n = 7\): \[ \sum_{m=1}^{7} m = \frac{7(7 + 1)}{2} = \frac{7 \times 8}{2} = 28. \] Now, combining these results gives: \[ \sum_{m=1}^{7} (1 + m) = 7 + 28 = 35. \] We substitute back into our summation expression: \[ -3 \sum_{m=1}^{7} (1 + m) = -3 \times 35 = -105. \] Thus, the value of the summation \[ \sum_{m=1}^{7}(-3-3 m) \] is \[ \boxed{-105}. \]