Question

the 9th term and the 17th term are 19 and 35 respectively . find the 25th term​

Answer 1

Answer:

51

Step-by-step explanation: 9th term = 19 , which is (9 * 2 = 18 ) + 1 = 19

similarly 17th term = 35 , which is (17 * 2 ) + 1 = 35 . So any term n in the sequence will be = (n * 2 ) + 1 . So the 25th term will be = to ( 25 * 2 ) + 1   = 51 .

Answer 2

Answer:

Step-by-step explanation:

9th term of AP = 19

We KNOW THAT 9TH TERM = A9 = a + 8d

                                                 a + 8d = 19 ------ (i)

Also given 17 th term = 35

that is a17 = 35

we know a17 = a + 16d = 35 ----- (ii)

Solving eq (i) and (ii) by elimination method

         a + 8d = 19

         a + 16d = 35

Changing signs we get,

       -8d = -16

        d = -16 / -8

        d = 2

Putting value of d in eq (i)

   a + 8d = 19

   a + 8(2) = 19

   a + 16 = 19      =     a = 19-16 = 3

so a=3 and d=2

so a25 = a + 24d

            = 3 + 2*24

            = 3 + 48

            = 51

Hope this answer helped you