5x x 2 3 ) x 2 7 5x )- 7x 2 July 8, 2019 16 32 64 128 5x x 2 3 )+ x 2 7 5x )- 7x 2 5x x 2 3 )+ x 2 7 5x )- 7x 2 tại x =- 5
