Answer :
Work backward: Multiply out (x-8i) and (x+8i).
The product is x^2 - [64i^2], or x^2 - [-64], or x^2 + 64
This is equivalent to 1x^2 + 0x + 64, and so a=1, b=0 and c=64.
The product is x^2 - [64i^2], or x^2 - [-64], or x^2 + 64
This is equivalent to 1x^2 + 0x + 64, and so a=1, b=0 and c=64.