Which of the following tables shows that y= kf(x) results in the parent function y= |x+4| being vertically stretched by a k factor of 3

x y=kf(x)
0 1
1 5
2 6

x y =kf(x)
0 -12
1 -15
2 -18

x y=kf(x)
0 12
1 15
2 18

x y=kf(x)
0 1.3
1 1.7
2 2

1 answer

To determine which table shows that \( y = kf(x) \) results in the parent function \( y = |x + 4| \) being vertically stretched by a factor of \( k = 3 \), we first need to understand how the transformation works.

The transformation \( y = kf(x) \) means that every output of the function \( f(x) \) (in this case, \( |x + 4| \)) is multiplied by \( k \). For a vertical stretch by a factor of 3:

\[ y = 3|x + 4| \]

We will find the values of \( |x + 4| \) at the given x values and multiply each by 3 to see what \( kf(x) \) should look like.

Now, let’s compute \( |x + 4| \) for the values of \( x = 0, 1, 2 \):

  • For \( x = 0 \): \[ |0 + 4| = 4 \quad \Rightarrow \quad y = 3 \times 4 = 12 \]

  • For \( x = 1 \): \[ |1 + 4| = 5 \quad \Rightarrow \quad y = 3 \times 5 = 15 \]

  • For \( x = 2 \): \[ |2 + 4| = 6 \quad \Rightarrow \quad y = 3 \times 6 = 18 \]

Based on these calculations, we expect the outputs for \( y = kf(x) = 3|x + 4| \) to be:

  • When \( x = 0 \), \( y = 12 \)
  • When \( x = 1 \), \( y = 15 \)
  • When \( x = 2 \), \( y = 18 \)

Now we compare this expected output with the choices:

\[ \begin{array}{|c|c|} \hline x & y = kf(x) \ \hline 0 & 1 \ 1 & 5 \ 2 & 6 \ \hline \end{array} \] (No matches)

\[ \begin{array}{|c|c|} \hline x & y = kf(x) \ \hline 0 & -12 \ 1 & -15 \ 2 & -18 \ \hline \end{array} \] (No matches)

\[ \begin{array}{|c|c|} \hline x & y = kf(x) \ \hline 0 & 12 \ 1 & 15 \ 2 & 18 \ \hline \end{array} \] (Matches perfectly!)

\[ \begin{array}{|c|c|} \hline x & y = kf(x) \ \hline 0 & 1.3 \ 1 & 1.7 \ 2 & 2 \ \hline \end{array} \] (No matches)

The correct table that shows the transformation of the parent function \( y = |x + 4| \) being vertically stretched by a factor of 3 is:

Table 3: \[ \begin{array}{|c|c|} \hline x & y = kf(x) \ \hline 0 & 12 \ 1 & 15 \ 2 & 18 \ \hline \end{array} \]