-
最佳答案:1.3/7 × 49/9 - 4/32.8/9 × 15/36 + 1/273.12× 5/6 – 2/9 ×34.8× 5/4 + 1/45.6÷ 3/8 –
-
最佳答案:(1)(2a+1 )(-a -1)(2)(-2a+1 )(-2a+1 )(3)(x +2y)(x2-2xy +4y2)4、(3x2+2x-5)(x- 2)5、-