#### Answer

$\dfrac{25}{\sqrt {38}}$

#### Work Step by Step

The formula to determine the distance formula for two vectors $a$ and $b$ is given by:
$d=\dfrac{| a \cdot b|}{|b|}$
Thus, we have $a \cdot b=-1(2)+(-1)(3)+(-4)(5)=-25$
and $|a \cdot b|=|-25|=25$
Now, $d=\dfrac{25}{ \sqrt {(2)^2+(3)^2+(5)^2}}=\dfrac{25}{\sqrt {38}}$