X 4 5x 2 9 July 8, 2019 16 32 64 128 X 4 5x 2 9 0 X 4 5x 2 9 factorise 5x 2 x 4 9x 23 3 5x 4 2 x 9 X 2 9x 9 =- 5x 4 X 4 6x 3 5x 2 54x 9x 2 45 5x 2 x 4 ≤ 9x 20 X 3x 9 4 5x 2 X 4 5x 3 9x 2 X 4 5x 2x 3 x 2 9 4 5x 9 )=- 2 x 7 X 4 )( 5x 9 )- x 2 16 0 F prime ( x )=- 5x 4 9x 2 X 4 5x 2 4 x 4 10x 2 9