Asked by Nathan

Factor over {complex numbers}

9x^2 + 49
Answered by Reiny
how about ...

(3x + 7i)(3x - 7i) ?


check:
(3x + 7i)(3x - 7i)
= 9x^2- 49i^2, but i^2= -1
= 9x^2 - 49(-1)
= 9x^2 + 49