If the seventh term of an AP is equal to 11times the eleventh term.find the 18th term of the Ap, given that the common difference is 5.

"seventh term of an AP is equal to 11times the eleventh term"

a + 6d = 11(a + 10d)
a + 6d = 11a + 110d
10a = -104d

but d = 5, so
10a = -520
a = -52

term(18) = a + 17d = ....