作业帮帮我算算这几题,一：（-x²)³－3x²(x⁴＋2x－x)二：2（x－2）²－(x＋2)²(x－3)三：求[(a＋b)²－(a－b)²－8a³b²]÷(4ab)的值,其中a=1,b=2
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/12 20:40:34
![帮我算算这几题,一：（-x²)³－3x²(x⁴＋2x－x)二：2（x－2）²－(x＋2)²(x－3)三：求[(a＋b)²－(a－b)²－8a³b²]÷(4ab)的值,其中a=1,b=2](/uploads/image/z/12484588-4-8.jpg?t=%E5%B8%AE%E6%88%91%E7%AE%97%E7%AE%97%E8%BF%99%E5%87%A0%E9%A2%98%2C%E4%B8%80%EF%BC%9A%EF%BC%88-x%26%23178%3B%29%26%23179%3B%EF%BC%8D3x%26%23178%3B%28x%26%238308%3B%EF%BC%8B2x%EF%BC%8Dx%29%E4%BA%8C%EF%BC%9A2%EF%BC%88x%EF%BC%8D2%EF%BC%89%26%23178%3B%EF%BC%8D%28x%EF%BC%8B2%29%26%23178%3B%28x%EF%BC%8D3%29%E4%B8%89%EF%BC%9A%E6%B1%82%5B%28a%EF%BC%8Bb%29%26%23178%3B%EF%BC%8D%28a%EF%BC%8Db%29%26%23178%3B%EF%BC%8D8a%26%23179%3Bb%26%23178%3B%5D%C3%B7%284ab%29%E7%9A%84%E5%80%BC%2C%E5%85%B6%E4%B8%ADa%3D1%2Cb%3D2)
帮我算算这几题,一：（-x²)³－3x²(x⁴＋2x－x)二：2（x－2）²－(x＋2)²(x－3)三：求[(a＋b)²－(a－b)²－8a³b²]÷(4ab)的值,其中a=1,b=2
帮我算算这几题,
一：（-x²)³－3x²(x⁴＋2x－x)
二：2（x－2）²－(x＋2)²(x－3)
三：求[(a＋b)²－(a－b)²－8a³b²]÷(4ab)的值,其中a=1,b=2
帮我算算这几题,一：（-x²)³－3x²(x⁴＋2x－x)二：2（x－2）²－(x＋2)²(x－3)三：求[(a＋b)²－(a－b)²－8a³b²]÷(4ab)的值,其中a=1,b=2
一.-x6：（-x²)³－3x²(x⁴＋2x－x)
=-x6 -3x6-6x3+3x3
=-2x6-3x3
二：2（x－2）²－(x＋2)²(x－3)
=2x2-8x+8-(x2+4x+4)(x-3)
=2x2-8x+8-x3-4x2-4x+3x2+12x+12
=-x3+x2+20
三：求[(a＋b)²－(a－b)²－8a³b²]÷(4ab)的值,其中a=1, b=2
=(a2+2ab+b2-a2+2ab-b2-8a3b2) ÷(4ab)
=(4ab-8 a3b2) ÷(4ab)
=1-2a2b
把a=1,b=2代入
=1-2*2
=-3