Question

Which of the following is a solution of x2 + 6x = −18? (1 point) Question 27 options: 1) x = 3 − 3i 2) x = −3 + 3i 3) x = −6 + 3i 4) x = 6 − 3i

Answer 1

Answer: x = -3 + 3i (option 2)

Explaination:

Quadratic equation:

x² + 6x = -18

Here we use the Completing the square method

Add both the side square of half coefficient of x

square of (half of 6)

3²=9

x² + 6x + 9 = -18 + 9

(x + 3)² = -9

taking square root both the side

x + 3 = √(-9) or x + 3 = -√(-9)

x + 3 = 3i or x + 3 = -3i

x = -3 + 3i

or

x = -3 - 3i