math.rationalize() made some mistakes

So I'm extremely happy with math.js, but I've had some problems with the following. Does anyone have a fix, I'm not sure what to do.

`(a - b) + (a + 2b)` was solved as `a - b + a + 2 b` and it should be `2a + b`

`2y + (3 - 4x) * 2 - 7x` was solved as `2 y - 8 * x - 7 * x + 6` and it should be `-15x + 2y + 6`

`2y + (3 + 4x) * 3 - 8x` was solved as `2 y - 8 * x + 9 + 12 * x` and it should be `4x + 2y + 9`