1^2 +2^2+••••+n^2=1/6n(n+1)(2n+1)
using maths induction ​

Hello,

We suppose the property true for n:

1²+2²+...+n²=n(n+1)(2n+1) / 6

and we are going to demonstrate that the property is true for n+1:

1²+2²+..+(n+1)²=(n+1)*(n+2)*(2n+3)/6

(n^3 - n)

= n(n-1)(n+1)

since it is divisible by 3 and 2 ,because it is a multiple 3 consecutive number

if, n-1 is odd then n+1 is also odd, then it is a multiple of 9

but if, n-1 is even then n+1 is also even, then it is a multiple of 4

so, largest multiple = max(9*2, 4*3) = max(18, 12) = 18

- 70

this is the answer for you hope it