Question

The first term of an AP is -7 and the common diference is 5 ,find its 18th term and the general term

Answer 1

Here we are given the first term of AP
i.e. 1)a=-7 and
2)common difference (d)=5
To find: 1)18 th term and
               2) general term
Solution:We know the formula to find the general term of an AP
i.e. tn= a+(n-1)d
  tn=-7+(n-1)5
tn=-7+5n-5
tn=5n-12

this is the general term of AP

2) The 18 th term of AP = 5n-12= 5*18-12=78

Hope this helped u :-)