I think you have to multiply them. If you have a calculator you can do it easily.
Answer:
the answer is the last one
Step-by-step explanation:
X = 4, y = 4
X = 2
y = 2
X × y =?
2 ×2 = 4
The cookies because if they have 100°C, after 30 seconds it loses half it‘s heat and now it only has 50°C.
After the next 30 seconds it loses again half the heat so it‘s 25°C.
You can theoretically continue this forever. It‘s exponential decay.
-5+(-4)
-5-4
-9
Therefore, -9 is the correct answer
