To solve this equation, first combine the constants on the left side:

(x-3 13/21) + 2 10/21 = (x-3 13/21) + (2 10/21)

Now add the two fractions:

13/21 + 10/21 = 23/21

Now the equation becomes:

(x-3) + 23/21 = 7 2/21

Now we can combine the whole numbers on the right side:

7 + 2 = 9

The equation now is:

(x-3) + 23/21 = 9

Now we can solve for x by isolating x:

x - 3 + 23/21 = 9
x - 3 = 9 - 23/21
x = 9 + 23/21 + 3
x = 189/21 + 23/21 + 63/21
x = (189 + 23 + 63)/21
x = 275/21

Therefore, the solution to the equation is x= 275/21 or x= 13 2/21