We have an arithmetic sequence with common difference of 2, because -4 - (-6) = -4 + 6 = 2; -2 - (-4) = -2 + 4 = 2; 0 - (-2) = 0 + 2 = 2; etc.
So, d = 2
We have the formula: an = a1 + (n-1) x d, where the initial term of arithmetic sequence is a1 = -6;
Then, a30 = -6 + (30 - 1 ) x 2 = - 6 + 29 x 2 = -6 + 58 = 52 ( this is the thirtieth term);
