Consider the numbered Java code below.

$1)$ int a $=20$;

$2)$ int b;

$3)$ double x $=3\mathrm{.}5$;

$4)$ String s $=$ "All";

$5)$ x $+=$ a;

$6)$ x$--$;

$7)$ a $/=4-1$;

$8)$ b $=$ s$.$length$()$;

$9)$ b $+=4$;

$10)$ System.out.println$("$a $="+$ a $+",$ b $="+$ b$)$;

$11)$ System.out.println$("$x $="+$ x $+"$

s $="+$ s$)$;

$($a$)$ Trace this sequence using a separate row for each statement.

$($b$)$ Confirm your output with a Java program that executes these commands.