* 17. Ryun runs in a race at a rate of 400 meters per minute. Use a unit (64) multiplier to convert 400 meters per minute to miles per minute. \( (1 \mathrm{mi} \approx 1600 \mathrm{~m} \).) Simplify. 18. a. \( (-2)^{2}-4(3)+(\sqrt{11})^{2} \) (15) (27). \( \frac{m^{2} b^{4} r^{3}}{r^{4} b^{4} m} \) 19. \( \frac{5}{12}-\frac{3}{4} \cdot\left(\frac{9}{5}\right)^{-1} \)

To convert the speed from meters per minute to miles per minute, we can use the given unit multiplier. Starting with 400 meters per minute, we multiply by the conversion factor: \( \frac{1 \text{ mile}}{1600 \text{ meters}} \). So, \( 400 \text{ m/min} \times \frac{1 \text{ mi}}{1600 \text{ m}} = 0.25 \text{ mi/min} \). Voila! Ryun is zooming along at a quarter of a mile every minute. For the expression \( (-2)^{2}-4(3)+(\sqrt{11})^{2} \), let's break it down step by step. First, calculate \( (-2)^{2} = 4 \). Then, \( -4(3) = -12 \), and \( (\sqrt{11})^{2} = 11 \). Putting it all together gives us \( 4 - 12 + 11 = 3 \). Your result is 3—easy peasy and not a bit underwhelming!