Translation:Yes, I am busy on weekdays.
I wrote "Yes,weekdays I will be busy" and DL rejected it saying I must use "Yes, weekdays, we're busy". Seriously...
Two months later, I'm sure you've learned by now but for anyone else:
はい - Yes
へいじつ - Weekday(s) (noun)
は - topic particle (on the topic of weekdays-)
いそがしい - Busy (い-adjective)
です - copula/verb "to be"
The kanji for "weekday" 平日 is made up of 平 'hei' (ordinary, plain) and 日 'jitsu' (day). So "ordinary day" or "non-holiday day"