https://www.chegg.com/homework-help/questions-and-answers/circuit-fig-p18-find-vq-following-cases-v-0-v-v-plusminus-3-v-v-plusminus-6-v-repeat-part--q17871244

https://www.chegg.com/homework-help/questions-and-answers/circuit-fig-pi8-find-vo-following-cases-v1-0v-v1-3-v-v-6-v-repeat-part-changed-30-k-ohm--c-q8440603