Given the function of the graph expressed as;
f(x) =- 2^x
Given
f(x) = 8
Required
The value of x
To get the value of x, we will simply substitute f(x) = 8 into the function of the graph given as shown;
f(x) = 2^x
8 = 2^3
2^3 = 2^x
Since the base value are the same, they will cancel out to have;
3 = x
Rearrange;
x = 3
Hence the value of x is 3. Option B is correct
