Page 21, ex. 3
https://drive.google.com/file/d/1jQHijdabkLFvhEStbO2l2MsBukp4TMT-/view?usp=sharing
Page 22, ex. 1
https://drive.google.com/file/d/16PuwqqW7DjRejXvx6-knAfdex4HBTRx6/view?usp=sharing
Page 23, ex. 2
https://drive.google.com/file/d/1RwfiY4OncmRCscrvs2K8fmQasfDf0Ycj/view?usp=sharing
Page 23, ex. 3, 4
https://drive.google.com/file/d/18u_SyxoU2yaMNNl83nw7ozS6LTYbYGXD/view?usp=sharing