Given:
The objective is to find the pattern and list out the next two terms in the sequence.
Step-by-step explanation:
a)
The given sequence is 5, 17, 29, 41....
Let's find the difference between the two successive terms of the sequence.

Thus, the common difference between each successive terms is 12.
Then, the next two terms can be calculated as,

Hence, the next two terms are 53 and 65.
b)
The given sequence is 18, 14, 10, 6...
Let's find the difference between the two successive terms of the sequence,

Thus, the common difference between each successive terms is -4.
Then, the next two terms can be calculated as,

Hence, the next two terms are 2 and -2.
c)
The given sequence is -9, 4, -8, 5, -7, 6.
Here it can be observed that starting from -9, the alternate numbers are increasing.
Then, the next number can be calculated by find the difference between those sequence provided with alternae places.

Thus, the common difference between each successive terms is 1.
Similarly, the commo difference between the series present inside is,

Then, the next two number will be,

Hence, the two numbers are -9, 4, -8, 5, -7, 6, -6, 7.