Question

The first three term of an AP are 3y -1; 3y+5
and 5y + 1 respectively then find ​

Answer 1

we know if a,b,c are terms of AP

2b= a+c

check the image

hope it helps

purple you

gn

:)

Answer 2

Answer:

in an AP t2-t1 = t3-t2

(3y+5)-(3y-1) = (5y+1)-(3y+5)

3y+5-3y+1    = 5y+1 -3y-5

          6          = 2y - 4

             10       = 2y

              10/2  = y

               y     =  5

hence the first term = 3y-1 = (3×5)-1

                                           = 15-1 = 14

hence first term of the AP is 14

another way to find: let a = 3y-1

                                       b  = 3y +5

                                      c   = 5y +1

in 3 consecutive terms of an AP middle term will be average of therother terms i.e, b = (a+c)/2