ss="anchor" aria-label="anchor" href="#arg-b"></a></dt>
<dd><p>if supplied, the vector of constants on the right hand side of the equations, of length matching
the number of rows of <code>A</code>.</p></dd>


<dt id="arg-vars">vars<a class="anchor" aria-label="anchor" href="#arg-vars"></a></dt>
<dd><p>a numeric or character vector of names of the variables.
If supplied, the length must be equal to the number of unknowns in the equations, i.e., 2.
The default is <code>c(expression(x[1]), expression(x[2]))</c