Who on earth...?

[girlyswot]

I cannot imagine the person who buys these:



People who aren't maths geeks aren't going to want them. And people like me would actually be moved to smash them to pieces. I suppose you might buy one for a maths geek you don't really like, just to watch them squirm.

Comments

[girlyswot.livejournal.com]

You have to multiply both terms in each bracket with both terms in the other bracket.

So it's:

x by x = x^2
x by -1 = -x
2 by x = 2x
2 by -1 = -2

The second and third terms can be combined to give: x^2 + x -2