2x 1 5x 4 4x July 8, 2019 16 32 64 128 1 2x 3x 2 4x 3 5x 4 series 1 2x 3x 2 4x 3 5x 4 4x 1 )(- 2x 7 )(- 5x 4 (- 2x 4 )( 5x 2 4x 1 4x 5 1 2x )= 4 5x 2 1x4-1 5x4 2x 5