Calaula las saguientes determinantes \( \begin{array}{ll}\text { a) }\left|\begin{array}{cc}-8 & 9 \\ -1 & 20\end{array}\right| & \text { b }\left|\begin{array}{ll}2 & \frac{1}{3} \\ \frac{1}{2} & -1\end{array}\right| \text { c) }\left|\begin{array}{cc}5 & -a \\ 2 a & 4 a^{2}\end{array}\right|\end{array} \)

The number of incarcerated adults N (measured in thousands) in a certain country can be approximated by the equation \( \mathrm{N}=-2.8 \mathrm{x}^{2}+72.4 \mathrm{x}+1914 \), where x is the number of years since 2000. In 2012 , the number of incarcerated adults peaked. How many adults were incarcerated in that year? There were \( \square \) incarcerated adults in 2012.

Greg drove at a constant speed in a rainstorm for 280 miles. He took a break, and the rain stopped He then drove 264 miles at a speed that was 9 miles per hour faster than his previous speed. If he drove for 14 hours, find the car's speed for each part of the trip. The rate of the car in the rain was

4. \( 4 x-2 x+2=2 x-2-2 x \)

Greg drove at a constant speed in a rainstorm for 280 miles. He took a break, and the rain stopped He then drove 264 miles at a speed that was 9 miles per hour faster than his previous speed. If he drove for 14 hours, find the car's speed for each part of the trip. The rate of the car in the rain was 35 mph . The rate of the car without the rain was \( \square \mathrm{mph} \).

VERTICAL A. \( 3 X+2=32 \)