Chapter 4 - Quadratic Functions - 4.4 Solving Quadratic Equations by the Square Root Property and Completing the Square - 4.4 Exercises - Page 349: 66

$d(m) = 0.25\left(m-18\right)^2-68$

The conversion of the function to the standard vertex form is self explanatory. All mathematical steps are shown below. $$ \begin{aligned} d(m)&=0.25 m^2-9 m+13\\ & = 0.25\left( m^2-\frac{9}{0.25} m\right) +13\\ &= 0.25\left( m^2-36m\right) +13\\ & = 0.25\left(m^2-36m+ 18^2 \right)+13-0.25\cdot 18^2 \\ & =0.25\left(m-18\right)^2-68. \end{aligned} $$