jarodcong
幼苗
共回答了23个问题采纳率:87% 举报
P44/8,把(x-1)当做一个整体,合并3(x-1)²-2(x-1)³-5(1-x)²+4(1-x)³的结果是(
-2(x-1)²-6(x-1)³).
3(x-1)²-2(x-1)³-5(1-x)²+4(1-x)³
=3(x-1)²-2(x-1)³-5(x-1)²+4(-(x-1))³
=-2(x-1)²-2(x-1)³-4(x-1)³
=-2(x-1)²-6(x-1)³
P44/9,把(m-n)当做一个整体,合并(m-n)²+2(m-n)-1/3(n-m)²-3m+3n的结果是( ).
(m-n)²+2(m-n)-1/3(n-m)²-3m+3n
=(m-n)²+2(m-n)-1/3(m-n)²-3(m-n)
=2/3(m-n)²-(m-n)
P46/22,已知x=3时,代数式ax³+bx+1的值是-2009,求x=-3时代数式的值.
a*3³+3b+1=-2009
27a+3b=-2010
x=-3时
代数式ax³+bx+1的值
a(-3)³+b*(-3)+1
=-27a-3b+1
=-(27a+3b)+1
=-(-2010)+1
=2011
1年前
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