How can I prevent −2x + 3 − 2 from turning into 3−2(x+1)?

[meramos]

When I use the simplify method of the mathjs library to simplify the expression -2x + 3 - 2, I expect to get -2x + 1, but instead I get 3−2(x+1). How can I prevent that factorization?

Here is an example of the code I have:

import * as math from 'mathjs';

const expression = "-2x + 3 - 2";
const simplifiedExpression = String(math.simplify(expression));

I am also having a similar issue with the expression 2x + 2, which is being simplified to 2(x+1).

[josdejong]

Thanks for reporting. Are you using the latest version of mathjs? I tried with the latest version of mathjs, this gives:

console.log(math.simplify('-2x + 3 - 2').toString()) // 1 - 2 * x
console.log(math.simplify('2x + 2').toString())      // 2 * (x + 1)

So it looks like the first case works ok but the second doesn't make much sense. To solve this we have to tune the rules of simplify.

Anyone able to help out here?

[gwhitney]

What's wrong with the simplification 2x + 2 -> 2(x + 1)? It has factored out a common factor, which is something we want simplify to do. I mean, shouldn't 10000x + 10000 simplify to 10000(x+1)? This is the same, just with a smaller number...