Answer:
2
Step-by-step explanation:
Use. A. Calculator
(2x -5y) + (x+y) =
2x - 5y +x + y =
3x -4y
This question requires you to know the lowest common multiple (LCM) of 5, 4 and 2. there are a few ways to do that. in this case the LCM would be 20. this means that in 20 year the science department would buy all 3 equipment at the same time