### Question 8 (Multiple Choice Worth 1 Point)
(Graphing Exponential Functions LC)

The exponential function [tex]\( t(x) \)[/tex] increases at a rate of [tex]\( 30\% \)[/tex] through the ordered pair [tex]\( (0, -1) \)[/tex] and is shifted down 5 units. What is the equation for the horizontal asymptote?
A. [tex]\( y = -1 \)[/tex]
B. [tex]\( y = 5 \)[/tex]
C. [tex]\( y = -5 \)[/tex]
D. [tex]\( y = 0 \)[/tex]

### Question 9 (Multiple Choice Worth 1 Point)
(Linear Functions MC)

A dog walker charges a standard fee of [tex]\( \$15 \)[/tex], plus [tex]\( \$10 \)[/tex] per hour for each dog that is walked. The linear function [tex]\( d(t) = 10t + 15 \)[/tex] models the dog walker's total earnings. What is the total charge for walking a dog for 2 hours?
A. [tex]\( \$25 \)[/tex]
B. [tex]\( \$35 \)[/tex]
C. [tex]\( \$45 \)[/tex]
D. [tex]\( \$55 \)[/tex]



Answer :

Let's address Question 8 step-by-step:

### Step-by-Step Solution

1. Identify the Growth Rate:
- The exponential function increases at a rate of [tex]\(30\%\)[/tex]. This growth rate does not directly affect the horizontal asymptote but is an important feature of the exponential function.

2. Determine the Initial Value:
- The function passes through the point [tex]\((0, -1)\)[/tex]. Therefore, when [tex]\(x = 0\)[/tex], [tex]\(t(x) = -1\)[/tex]. This is the initial value before any shifts are considered.

3. Apply the Vertical Shift:
- The exponential function is shifted down by 5 units. A vertical shift affects the entire graph of the function. Since the function is shifted downward by 5 units, the horizontal asymptote is also shifted downward.

4. Determine the Horizontal Asymptote:
- The horizontal asymptote of an exponential function [tex]\(f(x) = a(b^x) + c\)[/tex] is determined by the value [tex]\(c\)[/tex]. This is the value the function approaches as [tex]\(x\)[/tex] approaches infinity.
- Since the function is shifted down by 5 units, the horizontal asymptote will also be translated down by the same amount. If the original horizontal asymptote was [tex]\(y = 0\)[/tex] for a typical exponential function, shifting it down by 5 units results in a new horizontal asymptote of [tex]\(y = -5\)[/tex].

5. Conclusion:
- The horizontal asymptote of the exponential function, after considering the vertical shift, is [tex]\(y = -5\)[/tex].

Therefore, the correct answer is:
[tex]\[ y = -5 \][/tex]

Answer choice:
[tex]\[ \boxed{y = -5} \][/tex]

This solution addresses all the factors influencing the horizontal asymptote including the growth rate, initial value, and the vertical shift.