Question

the 4th term of A. p is 14 and it's 12th term 70 what is it's first term

Answer 1

hey aabid!!!
'here is ur answer!:)

let the first term be a and common diff be d.
given -
4th term= 14
∴a+(4-1)d=14
⇒a+3d=14 ....(i)

12th term=70
∴a+(12-1)d=70
⇒a+11d=70....(ii)

subtracting (i) from (ii),we get..
a+11d-(a+3d)=70-14
⇒8d=56
⇒d=7

then by putting the value of "d" in (i), we get...
a+3(7)=14
⇒a=14-21
∴a=  -7

ans- so the first term is '-7'.


hope it helps:) :) :) kindly check d answer

Answer 2

yes , its -7, u r corret