# What is the dot product of  (- 4 i - 5 j + 2) and (i + j -7k)?

$- 23.$
$\left(- 4 i - 5 j + 2 k\right) \cdot \left(i + j - 7 k\right) = \left(- 4\right) \left(1\right) + \left(- 5\right) \left(1\right) + \left(2\right) \left(- 7\right) = - 4 - 5 - 14 = - 23$.