Question

the seventh term of an AP is 30 and the tenth term is 21 find the fourth term plz ans

Answer 1

7th term = 30
10th term = 21
10-7 = 21-30
3rd term = -9
1st term = -9/3 = -3×2 = -6-9 = -15
4th term = -15 + 9 = -6

hope it is correct

Answer 2

seventh term of ap is t7 =a+6d=30 let this is equation 1
tenth term of ap is t10= a+9d=21 let this is equation 2
to find t4 of ap is
using elimination method
equation 1....... a+6d=30
equation 2.......a+9d=21
(-) (-) (-)
________
-3d= 9
________
then d= -9/3=(-3)
substituting d = -3 in equation 1
a+6d=30
a+6(-3)=30
a+(-18)=30
a-18=30
a=48
then t4= a+3d
=48+3(-3)
=48+(-9)
=48-9
=39
hence t4=39 respectively