5a³-3b²-5a³+4b²+2ab,其中a=-1,b=1/2
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![5a³-3b²-5a³+4b²+2ab,其中a=-1,b=1/2](/uploads/image/z/4334545-1-5.jpg?t=5a%26%23179%3B-3b%26%23178%3B-5a%26%23179%3B%2B4b%26%23178%3B%2B2ab%2C%E5%85%B6%E4%B8%ADa%EF%BC%9D-1%2Cb%EF%BC%9D1%2F2)
5a³-3b²-5a³+4b²+2ab,其中a=-1,b=1/2
5a³-3b²-5a³+4b²+2ab,其中a=-1,b=1/2
5a³-3b²-5a³+4b²+2ab,其中a=-1,b=1/2
答:
5a³-3b²-5a³+4b²+2ab,其中a=-1,b=1/2
=(5a³-5a³)+(-3b²+4b²)+2ab
=0+b²+2ab
=(b+2a)b
=(1/2 -2)*(1/2)
=(-3/2)*(1/2)
=-3/4
化简得b(b+2a) 将ab带入得 结果为负四分之三