Answered

The function [tex]$f$[/tex] is defined by [tex]$f(x) = (-8)(4)^x - 2$[/tex]. What is the [tex]y[/tex]-intercept of the graph of [tex][tex]$y = f(x)$[/tex][/tex] in the [tex]xy[/tex]-plane?

A) [tex]$(0,16)$[/tex]
B) [tex]$(0,-6)$[/tex]
C) [tex][tex]$(0,-8)$[/tex][/tex]
D) [tex]$(0,-10)$[/tex]



Answer :

To find the [tex]\( y \)[/tex]-intercept of the graph of the function [tex]\( f(x) = (-8)(4)^x - 2 \)[/tex], we need to determine the value of [tex]\( f(x) \)[/tex] when [tex]\( x = 0 \)[/tex]. This is because the [tex]\( y \)[/tex]-intercept occurs where the graph crosses the [tex]\( y \)[/tex]-axis, i.e., the point where [tex]\( x = 0 \)[/tex].

Here's a step-by-step solution:

1. Substitute [tex]\( x = 0 \)[/tex] into the function:
[tex]\[ f(0) = (-8)(4)^0 - 2 \][/tex]

2. Evaluate the expression inside the function:
[tex]\[ (4)^0 = 1 \][/tex]

3. Multiply by the coefficient:
[tex]\[ (-8) \times 1 = -8 \][/tex]

4. Subtract 2:
[tex]\[ -8 - 2 = -10 \][/tex]

So, the [tex]\( y \)[/tex]-intercept of the function is [tex]\((-10)\)[/tex]. In coordinate form, the [tex]\( y \)[/tex]-intercept is [tex]\((0, -10)\)[/tex].

Thus, the correct answer is:
[tex]\[ \text{(D) } (0, -10) \][/tex]