Question

3x+6x+9x+....+to n terms= 3/2n(n+1)x

Answer 1

3x + 6x + 9x + ......n terms they are in AP therefore, the common difference is 3x sum = n/2 [2.3x + (n - 1) 3x] =3*n (2 + n - 1)/2 =3/2 nx (1 + n) Hence proved !

Answer 2

Step-by-step explanation:

HOPE it will be helpful