Question

How do you graph `y=-2(2.5)^x`?

Answer 1

If the standard exponential `f(x)=2.5^x` is the "parent" graph, then the graph of `y` is the graph of `f(x)` scaled by 2 and reflected in the `x-`axis.

Explanation:

Consider the standard exponential graph `f(x) = (2.5)^x` below.

graph{2.5^x [-5.71, 5.39, -1.244, 4.306]}

If we take `f(x)` above as the "parent" graph, then the graph of `y` is the graph of `f(x)` scaled by 2 and reflected in the `x-`axis.

The graph of `y` is shown below.

graph{-2(2.5)^x [-5.757, 5.343, -4.107, 1.443]}