The first term of an ap are - 3 and 145, respectively if the common difference is 4 find the (a) 12th (b) 25 term
so we have
a = -3
d = 4
now just use your formula for the nth term.
a_n = -3 + 4(n-1) = 4n-7
not sure what the 145 is supposed to be ...