The function f(x) = x2 + 22x + 58 is translated 4 units to the right and 16 units up. What is the vertex form of the new function?

(x – 11)2 + 58
(x + 22)2 – 121
(x + 7)2 – 47
(x – 15)2 + 94

1 answer

To translate the function \( f(x) = x^2 + 22x + 58 \) 4 units to the right and 16 units up, we can follow the steps below:

  1. Translation to the Right: Translating a function to the right by \( h \) units means replacing \( x \) with \( x - h \). Here, \( h = 4 \). Thus, we replace \( x \) with \( x - 4 \):

    \[ f(x - 4) = (x - 4)^2 + 22(x - 4) + 58 \]

    Now, expand this:

    \[ = (x - 4)^2 + 22x - 88 + 58 \] \[ = (x - 4)^2 + 22x - 30 \]

    Now, we need to expand \( (x - 4)^2 \):

    \[ (x - 4)^2 = x^2 - 8x + 16 \]

    So, substituting that back, we get:

    \[ f(x - 4) = x^2 - 8x + 16 + 22x - 30 \] \[ = x^2 + 14x - 14 \]

  2. Translation Upwards: Translating a function upward by \( k \) units means adding \( k \) to the function. In this case, \( k = 16 \):

    \[ f(x - 4) + 16 = (x^2 + 14x - 14) + 16 \] \[ = x^2 + 14x + 2 \]

  3. Converting to Vertex Form: To write the new function in vertex form, we need to complete the square for \( x^2 + 14x + 2 \).

    \[ = (x^2 + 14x + 49) - 49 + 2 \] \[ = (x + 7)^2 - 47 \]

Thus, the vertex form of the new function after the required translations is:

\[ (x + 7)^2 - 47 \]

Therefore, the correct option from the given choices is:

\[ \boxed{(x + 7)^2 - 47} \]