How to make a smaller gap when using many level of ? [duplicate]

I have the following problem:

Where I'm using  twice to make the equation of the linear model fit horizontally.

But I don't like white space that's left between the two lines.

Is there a way to perhaps make the two lines with less white space between them?

• The vertical space around these equations is \abovedisplayskip and \belowdisplayskip. Nov 25 '16 at 17:30
• don't use repeated  use a multiline display such as align or split Nov 25 '16 at 17:31 • @DavidCarlisle Can you provide more info? Nov 25 '16 at 17:31 • there are loads of examples of split on site, see egregs answer here: Nov 25 '16 at 17:33 • @mavavilj: Are you talking specifically about using  in MathJax?
– Werner
Nov 25 '16 at 17:49