In the book we have the following image for D7:
But every other resource I consult, all 7th chords have 4 notes (this only has 3).
What's on the book seems to match the 1st inversion for D7 (minus the A note):
Q: Is the book just omitting this information to avoid confusing readers (since we're just starting out)?
I'm afraid that I'll have to go back and re-relearn these chords(D7 is not the only example) with the proper names/inversions