Factorise completely the expression

\((x + 2)^2\) - \((2x + 1)^2\)

Find  the \(n^{th}\) term of the sequence 2 x 3, 4 x 6, 8 x 9, 16 x 12...

If 3x\(^o\) 4(mod 5), find the least value of x

Find the inter-quartile range of 1, 3, 4, 5, 8, 9, 10, 11, 12, 14, 16

If  x : y = \(\frac{1}{4} : \frac{3}{8}\) and y : z = \(\frac{1}{3} : \frac{4}{9}\), find x : z