问题 填空题

已知4x2-3x+1=a(x-1)2+b(x-1)+c对任意数x成立,则4a+2b+c=______

答案

∵a(x-1)2+b(x-1)+c

=a(x2-2x+1)+bx-b+c

=ax2-2ax+a+bx-b+c

=ax2-(2a+b)x+a-b+c

=4x2-3x+1

∴a=4、-(2a+b)=-3、a-b+c=1,

解得:a=4、b=-5、c=-8,

∴4a+2b+c

=4×4+2×(-5)+(-8)

=16-10-8

=-2

故答案为:-2.

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