Thank you for your help. I want to ask one more question. I am new in Maple so my question will be silly.

When I am working in Maple I just type for example "2+3" it works and I get the result.

However when I write 

eqn := a*b*c = sqrt(a+2)*d*e;

I doesnt work and when I type enter nothing will done.

I dont understand why?

Thank you for your help Carl Love 13265. But it doesnt work anyway.