Some Chords

Here is a method to remember easily the extensions of the chords against a certain root (R) starting from simple major, minor, maj7 and 7-chords. x stands for muted string:

The next table shows the correspondence between the root of the scale and the fret on the guitar where a certain chord should be played. For instance, if you want to play in the root of A, you should start (n=) at the 5^th or 17^th fret, for the root of C, you should start at the 8^th or 20^th fret, for the root of Eb, you should start at the 11^th fret: