Number Systems

$($a$)$ In a base$-7$ number system, suppose we have the number $526?$ What is the

value in base$-10$ of the underlined digit?

$[$

$]$

$($b$)$ What is $0$xbef$5$ in binary? $($Example: $0$b$101\_0101\_0101,$ with $0$b as prefix and

underscore between every $4$ digits$)$

$($c$)$ What is $101\_1011\_1110\_1001$ in hexadecimal? $($use lower case letters and prefix

your answer with $\text{'}0$x$\text{'}($zero followed by $x).$

$[$

$]$