$($a$)\{$w $|$; w contains exactly two bs$,$ or an even number of as$\}$

$($b$)\{$w $|$ w contains as substring ababb and$/$or bbb $\}.$

$($c$)\{$w $|$ w is any string except the two strings abba and aba$\}$

Give regular expressions generating the languages of Exercise $1.$ For $($a$),$ prove $($by induction$)$

that the language of your expression is equal to the language as described in $($a$).$