Maths or Math?

Whatever you want to call it, and I think this depends on what part of the world you are from, its all a bit too difficult for me now. Help with homework ceased a long time ago.

The image is of my sons homework, which is, I am told, an advanced higher (Scottish system) question. It doesn't seem to matter that he is 15 and not sitting these for another 2 years, they still get it for homework these days.

If I didn't have a sore head yesterday, I do tonight.