The last term is 58. List out the ways to multiply two whole numbers to get to 58
1*58 = 58
2*29 = 58
(-1)*(-58) = 58
(-2)*(-29) =58
Then go through those factors and see which two values add to 6 (which is the middle number in the given expression)
1+58 = 59
2+29 = 31
-1+(-58) = -59
-2+(-29) = -31
None of those sums are 6, so the original expression cannot be factored. It is said to be prime.