[Tex/LaTex] How to remove space after `\right`

Question

Why is it that after \right), the . placed after it is spaced. It looks disturbing.
For example:

\begin{equation}
\left(x+y=z\right).
\end{equation}
There exists an automatic slight space between ) and . that I would like to get rid of if possible?
EDIT:
Here is a better example,

\begin{equation}
\begin{aligned}
4x+y-z =& \left( \int_3^7 dr+ \right. \\
    & \left. y+x\mathcal{M} \right).
\end{aligned}
\end{equation}

What has been discussed in the comments, is to define \usepackage{mleftright} though without an application, things are still a little difficult to understand.

Answer 1

Your example produces

Which has extra space as the two \left\right pairs make \mathinner atoms which typically get \thinmuskip space around them (the same space as \, which is 1.7pt here) and additional \nulldelimiterspace (1.2pt here) from the two invisible delimiters \right. on the first line and \left. on the second.

However far more disturbing than this white space is the mis-matched size of the ().

If you use fixed size delimiters all these problems go, the brackets are the same size, and there are no null delimiters or mathinner groups creating unwanted horizontal space. I also brought the + on to the next line. If you do want it at the end of the first line it should be marked up as +{} so that it keeps its infix spacing, aligned only automatically supports the convention where binary operators start the continuation line as used below.

(The remaining white space between the ) and . is not white space added by TeX it is white space within the font's glyph for the ) character.

\begin{equation}
\begin{aligned}
4x+y-z =& \Bigl( \int_3^7 dr  \\
    & + y+x\mathcal{M} \Bigr).
\end{aligned}