SOLUTION: Can you please help me understand the method of arriving at the answer of this problem? Thank you. In my textbook this was the exercise question Write the product in standard

   F        O          I         L       
(2)(2) + (2)(-i) + (3i)(2) + (3i)(-i)

   4   -   2i    +    6i   -   3i²

             4 + 4i - 3(-1)
           
              4 + 4i + 3

                7 + 4i



The answer in the back of the book was 
X= -4 +or- the sqrt of the fraction 8/3. 

I don't understand how they arrived at this answer.

I don't either. I think you looked at the answer
to this problem instead:

Solve for x by completing the square:

       3x² + 24x + 40 = 0

            3x² + 24x = -40

              x² + 8x = 

8·1/2 = 4, 4² = 16, so add + 16 to both sides

         x² + 8x + 16 =  + 16

       (x + 4)(x + 4) =  + 

             (x + 4)² = 

Use square root principle:
                         
                x + 4 = ±

                    x = -4 ± 

Edwin