More help needed.

I do not have solver installed on my PC and the logistics of getting it
put onto every PC at work is going to be impossible. So I can't use
the solver. I do have GoalSeak if thats any help.

Next although the y-value for this equation is near zero that will not
be the case in all the eqautions i deal with. the equations are just
an example.

I want to know at what X-value do the two lines cross.

I would preferably want it as an eqaution because I need to construct
it using XL. Also I have done much in the way of mathematics since uni
(about 7 years ago) so you will have to go slow. I know it's a
terrible excuse, but I need to understand it all.

mc+c=c^bx (^=exp).