Question

second term of an ap is 7 more than 6th term of ap and 8th term of ap is 70 find ap and 100th of the ap​

Answer 1

Answer:

given second term of the AP is 7 more than 6th term of ap and 8th term of ap is 70.

we can write second term of the AP = $a_{2}$ = a +(2-1)d

                                                                  = a + d

 similarly 6th term of the AP     = a + 5d

according to the question

second term of the AP - 6th term of the AP = 7

         (a+d) - (a+5d)   = 7

          a +d-a-5d        = 7

                        -4d      = 7

                           d   = -4/6 = -2/3

given 8th term of the AP = 70

          a + (n-1)d   =a(n)

          a + (8-1)(-2/3) = 70

           a+( 7 ) (-2)    = 70× 3

                     a + 7= 210/-2

                           = -105

                        a = -105 -7

                            a = -112

a(100) = -112+(100-1)(-2/3)

           = -112 + 99 (-2/3)

             = -178

Answer 2

Answer:

given second term of the AP is 7 more than 6th term of ap and 8th term of ap is 70.

we can write second term of the AP =  = a +(2-1)d

                                                                 = a + d

similarly 6th term of the AP     = a + 5d

according to the question

second term of the AP - 6th term of the AP = 7

        (a+d) - (a+5d)   = 7

         a +d-a-5d        = 7

                       -4d      = 7

                          d   = -4/6 = -2/3

given 8th term of the AP = 70

         a + (n-1)d   =a(n)

         a + (8-1)(-2/3) = 70

          a+( 7 ) (-2)    = 70× 3

                    a + 7= 210/-2

                          = -105

                       a = -105 -7

                           a = -112

a(100) = -112+(100-1)(-2/3)

          = -112 + 99 (-2/3)

            = -178