Melody

parentheses (curly brackets) are used for sets. 

{ } is an empty set.

meaning that there are no solutions.  

Thanks for you nice words too.  

So I did - thanks Chris. :)

use the calc on  the home page

Yes  all the time :)

Try looking at this.

only one and 127 goes into 127 

but

127 goes into any multiple of 127

eg

it goes into 254,

(7+9i)-(2-i)

=7+9i-2+i

=5+10i

-3*-3=9

that is the answer

$$\frac{8}{3}= 2\frac{2}{3}$$