Analyze x² + 10x + 25: Exploring Positive and Negative Domains

Question

Find the positive and negative domains of the function below:

y=x2+10x+25 y=x^2+10x+25

Step-by-Step Solution

To solve this problem, follow these steps:

  • Step 1: Factor the quadratic function or recognize it as a perfect square trinomial.
  • Step 2: Identify the vertex of the parabola.
  • Step 3: Analyze the intervals between roots and the surrounding areas to determine positivity or negativity.

Now, work through these steps:

Step 1: Recognize the quadratic function y=x2+10x+25 y = x^2 + 10x + 25 as a perfect square trinomial. It can be rewritten as y=(x+5)2 y = (x + 5)^2 .

Step 2: The vertex of the parabola, which also represents its minimum point since the parabola opens upwards, occurs at x=5 x = -5 .

Step 3: Since (x+5)20 (x + 5)^2 \geq 0 for all real x x (because a square is always non-negative), the function is non-negative everywhere.

Therefore, the function is never negative, and since it equals zero at x=5 x = -5 , it is positive for all x5 x \neq -5 .

Therefore, the function's positive domain is x>0:x5 x > 0 : x \neq -5 . For x<0 x < 0 , the function is not negative, hence there is no such domain.

The solution to the problem is:

x > 0 : x \neq -5

x < 0 : none

Answer

x > 0 :x\ne-5

x < 0 : none