# Math Help - Does this simplification make sense?

1. ## Does this simplification make sense?

(z-3)(z^2 + 25)
(z-3)((z + 5)^2 - 10z)
(z-3)(z + 5 + i)(z + 5 - i)

Does it make sense?

2. how did you get the third line from the second?

$(z-3)(z^2+25) = (z-3)(z+5i)(z-5i)$ looks better

3. Originally Posted by Taluivren
how did you get the third line from the second?

$(z-3)(z^2+25) = (z-3)(z+5i)(z-5i)$ looks better
I'm not sure, that's why I was wondering. I thought that if I subtracted 10 it would even out the equation and I could leave it as a complex number, but after re-working it I found your way much more helpful (and correct ).