The diagonals of a are always perpendicular. a) parallelogram b) quadrilateral c) rectangle d) rhombus

Properties:

The diagonals of a parallelogram always bisect each other.

The diagonals of a quadrilateral just intersect in the case of a convex quadrilateral.

The diagonals of a rectangle bisect each other. The diagonals are always equal.

The diagonals of a rhombus bisect each other at 90°.

Hence The diagonals of a Rhombus are always perpendicular.

Option D) is the right 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