问题
解答题
(1)一个多项式减去-4x2-2x+1等于3x2+4x-1,求这个多项式. (2)先化简,再求值:
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答案
(1)-4x2-2x+1+(3x2+4x-1)
=-4x2-2x+1+3x2+4x-1
=-4x2+3x2-2x+4x-1+1
=-x2+2x;
(2)
a-2(a-1 2
b2)+(-1 3
a+3 2
b2)1 3
=
a-2a+1 2
b2-2 3
a+3 2
b21 3
=-3a+b2;
当a=-2,b=
时,2 3
原式=-3×(-2)+(
)2=6+2 3
=64 9
.4 9