Question

If the graph is decreasing from left to right, which of the following equations may be represented by it.
1. y = 2^x + 1
2. y = -2^-x + 1
3. y = 2^-x – 1
4. y = 2^-x + 1

Answer 1

3 and 4

Answer 2

Why is it 3 and 4?