One of the solutions to the equation x3+5x2+10x+50=0 is −5 . Find the full solution set. Which of the following options correctly describes the solution set? Option #1: It has one real solution and two non-real solutions. Option #2: It has one non-real solution and two real solutions. Option #3: It has three real solutions. (1 point) Option #

1 answer

To find the full solution set for the equation \( x^3 + 5x^2 + 10x + 50 = 0 \) given that one solution is \( x = -5 \), we can use polynomial long division to factor the cubic polynomial.

  1. Use polynomial long division to divide \( x^3 + 5x^2 + 10x + 50 \) by \( x + 5 \):

    \[ x^3 + 5x^2 + 10x + 50 \div (x + 5) \]

    • The first term is \( x^2 \). Multiply \( x + 5 \) by \( x^2 \): \[ x^3 + 5x^2 \] Subtract: \[ (x^3 + 5x^2 + 10x + 50) - (x^3 + 5x^2) = 10x + 50 \]

    • The second term is \( 10 \). Multiply \( x + 5 \) by \( 10 \): \[ 10x + 50 \] Subtract: \[ (10x + 50) - (10x + 50) = 0 \]

    Therefore, we have: \[ x^3 + 5x^2 + 10x + 50 = (x + 5)(x^2 + 10) \]

  2. Find the solutions of the quadratic \( x^2 + 10 = 0 \):

    Solving for \( x \): \[ x^2 = -10 \] \[ x = \pm i\sqrt{10} \]

  3. The full solution set for the original cubic equation is:

    • One real solution: \( -5 \)
    • Two non-real solutions: \( i\sqrt{10} \) and \( -i\sqrt{10} \)

Based on the analysis above, the solution set consists of:

  • One real solution and two non-real solutions.

Therefore, the correct option is: Option #1: It has one real solution and two non-real solutions.