(2x-1)^2 -(3x+1)(3x-1)+5x(x-1),其中x=2/9 急 急!
问题描述:
(2x-1)^2 -(3x+1)(3x-1)+5x(x-1),其中x=2/9 急 急!
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