jazzing up triad progressions with 7th chords

example 1

purple writing is major scale formula

example 2

example 3

green writing at bottom is minor scale formula

example 4

example 5

| Am | D | G | C |

becomes

| Am7 | D7 | Gmaj7 | Cmaj7 |

Am7 D7 Gmaj7 Cmaj7
x022010 xx0212 320002 x32000

example 6

| Em | G | Am | C |

| Em | G | Am | C |

| Dsus | D | C | % |

| Em | G | Am | C | Em ||

becomes

| Em7 | Gmaj7 | Am7 | Cmaj7 |

| Em7 | Gmaj7 | Am7 | Cmaj7 |

| D7sus | D7 | C | Cmaj7 |

| Em7 | Gmaj7 | Am7 | Cmaj7 | Em7 ||

Em7 Gmaj7 Am7 Cmaj7 D7sus D7
020000 320002 x02010 x32000 xx0213 xx0212

example 7

example 8

example 9

(the original progression in black had 7th chords, and they were stripped away to make it easier to play)