Use the table to answer the question.

x f(x)=x3+1 g(x)=x+1
−2 −7 −1
−1 0 0
0 1 1
1 2 2
2 9 3
Compare the functions f(x)=x^3+1 and g(x)=x+1 . Which of the following statements is true about the intercepts of the functions?

(1 point)
Responses

Both functions have a y-intercept of (−1,0) and an x-intercept of (0,1).

The graphs intersect at (1,2).

The x- and y-intercepts are different for each function.

Both functions have an x-intercept of (−1,0) and a y-intercept of (0,1).

1 answer

To analyze the functions \( f(x) = x^3 + 1 \) and \( g(x) = x + 1 \), we need to identify their intercepts.

  1. Finding the y-intercept:

    • The y-intercept occurs where \( x = 0 \).
    • For \( f(0) = 0^3 + 1 = 1 \) → y-intercept is \( (0, 1) \).
    • For \( g(0) = 0 + 1 = 1 \) → y-intercept is \( (0, 1) \).
  2. Finding the x-intercept:

    • The x-intercept occurs where \( f(x) = 0 \) and \( g(x) = 0 \).
    • For \( f(x) = 0 \): \( x^3 + 1 = 0 \) → \( x^3 = -1 \) → \( x = -1 \) → x-intercept is \( (-1, 0) \).
    • For \( g(x) = 0 \): \( x + 1 = 0 \) → \( x = -1 \) → x-intercept is \( (-1, 0) \).
  3. Checking the intersection points:

    • To find where the graphs intersect, set \( f(x) = g(x) \): \[ x^3 + 1 = x + 1 \] \[ x^3 = x \] \[ x(x^2 - 1) = 0 \] This gives us \( x = 0 \) or \( x^2 = 1 \) (so \( x = 1 \) or \( x = -1 \)).
    • Evaluating these:
      • For \( x = -1 \): \( f(-1) = 0 \) and \( g(-1) = 0 \) → they intersect at \( (-1, 0) \).
      • For \( x = 0 \): \( f(0) = 1 \) and \( g(0) = 1 \) → they intersect at \( (0, 1) \).
      • For \( x = 1 \): \( f(1) = 2 \) and \( g(1) = 2 \) → they intersect at \( (1, 2) \).

Now evaluating the statements:

  • Statement 1: "Both functions have a y-intercept of (−1,0) and an x-intercept of (0,1)." – False.
  • Statement 2: "The graphs intersect at (1, 2)." – True.
  • Statement 3: "The x- and y-intercepts are different for each function." – False (they share x- and y-intercepts).
  • Statement 4: "Both functions have an x-intercept of (−1,0) and a y-intercept of (0,1)." – True, but only the x-intercept statement is correct since they have the same intercepts.

Thus, the true statements are that "The graphs intersect at (1,2)" and "Both functions have an x-intercept of (−1,0) and a y-intercept of (0,1)".

The best response based on the question is:

The graphs intersect at (1, 2).