Factor over {complex numbers}
9x^2 + 49
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
9x^2 + 49
(3x + 7i)(3x - 7i) ?
check:
(3x + 7i)(3x - 7i)
= 9x^2- 49i^2, but i^2= -1
= 9x^2 - 49(-1)
= 9x^2 + 49