To find the common difference in the sequence -2, -11, -20, -29, we can subtract each term from the previous one.
Starting with the second term, -11, we subtract the first term, -2:
-11 - (-2) = -11 + 2 = -9
Next, we subtract the third term, -20, from the second term, -11:
-20 - (-11) = -20 + 11 = -9
Finally, we subtract the fourth term, -29, from the third term, -20:
-29 - (-20) = -29 + 20 = -9
Therefore, the common difference in the sequence is -9.