That look is more late 60's than the 70's or maybe very early 70's, hot pants, miniskirts and white boots were quickly replaced by Disco fashions, oh the horror! Her hairstyle more closely matches the "Flipped Bob" made popular by Jackie Kennedy and others in the 60's.
@NoGamesTolerated John Tavolta mostly got his start on a 70's TV show called "Welcome Back, Kotter" and he and the other guys in Kotter's remedial class were called "Sweathogs".
@helenS As someone who grew up in the 70's, yes there was plenty of bad taste to go around but nothing to compare with the "New Wave" looks of the early 80's, look up "Flock of Seagulls" if you doubt this.
@helenS Oh my eyes, my eyes will never be the same again, girls wearing a garbage bag with a belt! Totally agree, think the New Wave was supposed to be the polar opposite of good music, or they sure tried hard to make it seem that way, lots of synthesizers and little talent 🙃