Question

Find the 60th term of the arithmetic sequence −29, -49, −69,

Answer 1

We see, the second number is 20 less than the first number, the third number is 20 less than the second number, ..

So, the pattern is : We minus 20 from a term to get the next term right after.

From the 1st term to the 60th term, there are 59 spaces.
Therefore, the 60th term = -29 - 59 x 20 = -1209