1) I bet you mean
16-25x² = (4-5x)(4+5x)
Otherwise the best that can be done is
(4-5i*x)(4+5i*x)
You take the sqrt of each of the two terms, once with a minus between them and again with a plus between them.
Try the second by yourself.
Please do NOT double post. If you don't like the answer, complain inthe original thread.
