My tex code

```
\documentclass[twocolumn]{article}
\usepackage{amsmath, amsfonts, amssymb, textcomp}
\usepackage[T4, OT1]{fontenc}
\usepackage{newunicodechar}
\usepackage{unicode-math}
\usepackage{multirow}
\newunicodechar{ƒ}{{\fontencoding{T4}\fontfamily{cmr}\selectfont\m f}}
\newunicodechar{Ƒ}{{\fontencoding{T4}\fontfamily{cmr}\selectfont\m F}}
\begin{document}
\begin{equation}
\begin{align}
x\left(a + \left(b-a\right) &\frac{k-1}{N}\right)\\
&= \lambda x y
\end{align}
\end{equation}
\end{document}
```

and I get the output

**How can you automatically size the brackets with \left and \right?**

## Best Answer

Assuming that this is the result you wanted to achieve:

this is a MWE to obtain it:

And these are the errors in your MWE:

`align`

environment inside an`equation`

. If you want a single equation just use`equation`

(with no alignment characters`&`

inside). If you want multiple aligned equations use`align`

. But, as in your case, if you want to align stuff inside a single equation, use a`split`

environment inside an`equation`

.`\left`

and`\right`

to "automatically size the brackets" they have to be in the same equation and there should be no`&`

between them. You can use`\left.`

and`\right.`

to match the missing pairs, but in your case this doesn't work well because`\left`

and`\right`

are applied to things with different size. In this case (and probably always) is much better to use fixed size commands like`\biggl`

and`\biggr`

.