(2x-1)^2 -(3x+1)(3x-1)+5x(x-1),其中x=2/9 急 急!
人气:315 ℃ 时间:2019-09-22 07:44:28
解答
(2x-1)^2 -(3x+1)(3x-1)+5x(x-1)
=(4x²-4x+1)-(9x²-1)+5x²-5x
=-9x+2
=-9*(2/9)+2
=0
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