Solve |x|> 3 a.{-3,3} b.{x|x< -3 u x> 3} c.{x|x< -3ωx> 3}

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).