Hi David, do not be daunted! Algebra is mostly logic with x's and y's. The dreaded word 'unknown' is simply something you are working towards.
When I was about 10 and about to attend a secondary school I pestered my older cousin to tell me what 'x' equalled, as I thought it would save me a lot of trouble in the future!
The last few years I have used it just once per year. We have an annual exhibition and sell similar tickets to adults and children. If you know how much money was taken in tickets and the number of tickets sold then you can work out how many adults and how many children bought tickets.
Otherwise it does not come into frequent use!
Good luck with it though.
kind regards,
Roy