Solve the system of equations.

x + 3y = -1
2x + 2y = 8

(-4,1)
(2,-1)
(4,-1)
(5,-2)

(5,-2) is the answer

(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