قَامَ زَيْدٌ وَعَمْرٌو: ʿAmrun is a nominative coordinate sharing the subject relation.
ضَرَبْتُ أَنَا وَزَيْدٌ: anā reinforces the attached subject; Zaydun is its nominative coordinate.
مَرَرْتُ بِكَ وَبِزَيْدٍ: bi- is repeated; Zaydin is genitive.
For each sentence, identify the governor, first term, conjunction and coordinate before moving on.