Solve y = x² + 8x + 20: Finding Values Where Function is Negative

Question

Look at the following function:

y=x2+8x+20 y=x^2+8x+20

Determine for which values of x x the following is true:

f(x) < 0

Step-by-Step Solution

To identify for which values of x x the function y=x2+8x+20 y = x^2 + 8x + 20 is negative, we will analyze the quadratic equation:

  • Step 1: Identify the coefficients: a=1 a = 1 , b=8 b = 8 , c=20 c = 20 .
  • Step 2: Calculate the discriminant Δ=b24ac \Delta = b^2 - 4ac .
  • Step 3: Evaluate whether the parabola intersects the x-axis based on the discriminant.

Calculating the discriminant:
Δ=824120=6480=16 \Delta = 8^2 - 4 \cdot 1 \cdot 20 = 64 - 80 = -16 .

The discriminant Δ=16 \Delta = -16 is less than zero, which means there are no real roots. The parabola does not intersect the x-axis and opens upwards because the coefficient a is positive.

Therefore, the values of y=x2+8x+20 y = x^2 + 8x + 20 are always greater than zero for all real x x . The quadratic function does not take negative values for any real x x .

The correct answer is: The function has no negative values.

Answer

The function has no negative values.