Given the equation: f(x) = 2x^2 + 4x + 96

a.) State f(x) in factored form.

b.) State the roots of f(x)

1 answer

To factor the quadratic function \( f(x) = 2x^2 + 4x + 96 \) and find its roots, we can follow these steps:

a.) Factored form of \( f(x) \)

  1. First, we can factor out the common coefficient of 2 from the quadratic: \[ f(x) = 2(x^2 + 2x + 48) \]

  2. Next, we can factor the quadratic \( x^2 + 2x + 48 \). To do this, we can use the quadratic formula or check for factors, but since 48 has no pairs of factors that add to 2, the quadratic does not factor nicely into rational numbers.

  3. Therefore, \( x^2 + 2x + 48 \) does not have real roots, and we can use the quadratic formula to express it. The roots are given by: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1 \), \( b = 2 \), and \( c = 48 \).

    Calculate the discriminant: \[ b^2 - 4ac = 2^2 - 4 \times 1 \times 48 = 4 - 192 = -188 \]

    Since the discriminant is negative, the factorization will involve complex numbers. Thus, we find: \[ x = \frac{-2 \pm \sqrt{-188}}{2} = \frac{-2 \pm \sqrt{188}i}{2} = -1 \pm \sqrt{47}i \]

  4. Hence, the factored form in terms of complex numbers, using the roots found, is: \[ f(x) = 2 \left( x - (-1 + \sqrt{47}i) \right) \left( x - (-1 - \sqrt{47}i) \right) \] or, more neatly, \[ f(x) = 2 \left( x + 1 - \sqrt{47}i \right) \left( x + 1 + \sqrt{47}i \right) \]

b.) Roots of \( f(x) \)

The roots of the function \( f(x) = 2x^2 + 4x + 96 \) are: \[ x = -1 + \sqrt{47}i \quad \text{and} \quad x = -1 - \sqrt{47}i \]

Thus, we can summarize:

  • Factored Form: \( f(x) = 2(x + 1 - \sqrt{47}i)(x + 1 + \sqrt{47}i) \)
  • Roots: \( x = -1 + \sqrt{47}i \) and \( x = -1 - \sqrt{47}i \)