How do you recognized a rhythming s
scheme or patern

You can recognize a rhythmic scheme or a pattern by analyzing the number or feet in a verse. A foot consists of 2 syllables. That is why the most famous scheme in English poetry is called the Pentameter. That means that there are 5 feet, or, 10 syllables. There are various other options, however, such as the tetrameter, hexameter, trimeter, etc. Based on the position of the accent in a foot, a foot can be iambic, trochaic, anapestic, or dactylic. It can be many types more, but these four are most common.

It's simple

You just add 2x with 4x. That is, remove the parentheses and add up.

4x + (2x+y) -8 =

4x + 2x + y - 8 =

6x + y -8