Chapter 1 - Functions and Their Graphs - Section 1.7 Building Mathematical Models Using Variation - 1.7 Assess Your Understanding - Page 109: 19

$F=6.67\times10^{-11}(\frac{mM}{d^2})$

Step 1. Write the general form as $F=\frac{GmM}{d^2}$ where $k$ is a constant. Step 2. Use the given condition, $G=6.67\times10^{-11}$ Step 3. We have $F=6.67\times10^{-11}(\frac{mM}{d^2})$