The correct statement about the graph of an exponential decay function in the form \( y = a(b)^x \), where \( 0 < b < 1 \), is:
The domain includes all real numbers, the y-intercept is at (0,a), and the horizontal asymptote is at y=0.
This is because:
- The function is defined for all real values of \( x \), making the domain all real numbers.
- The y-intercept, found by evaluating the function at \( x = 0 \), is \( y = a(b)^0 = a \).
- As \( x \) approaches infinity, \( y \) approaches 0, giving the horizontal asymptote at \( y = 0 \).
Thus, this response accurately describes the properties of the graph of an exponential decay function.