Here's a fun one... How would you solve a basic simultanous equation with PHP?

I have an array with a range [high,low] of [378,395] and I want to normalise the data in that array between the values of [-1, 1].

From that, using `x => ax + b`

you get the two equations:

378a + b = -1

395a + b = 1

Obviously this is quite easy to solve on paper...But I wouldn't have a clue how to go about it in PHP. A quick google search reveals a scary lack of information :/