Answer:
13y² - 6z
Step-by-step explanation:
Amount spent per month = 5y²-2z
Amount saved per month = 8y²-4z
Amount earned per month = (Amount saved per month + Amount spent per month)
Amount earned per month :
8y²-4z + 5y²-2z
8y² + 5y² - 4z - 2z
13y² - 6z