已知a-b=1,则a²-b²-2b的值为1.我要过程已知x²-x-1=0,则-x的立方+2x²+2009的值为多少?要过程!!!
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![已知a-b=1,则a²-b²-2b的值为1.我要过程已知x²-x-1=0,则-x的立方+2x²+2009的值为多少?要过程!!!](/uploads/image/z/1024735-31-5.jpg?t=%E5%B7%B2%E7%9F%A5a-b%3D1%2C%E5%88%99a%26%23178%3B-b%26%23178%3B-2b%E7%9A%84%E5%80%BC%E4%B8%BA1.%E6%88%91%E8%A6%81%E8%BF%87%E7%A8%8B%E5%B7%B2%E7%9F%A5x%26%23178%3B-x-1%3D0%EF%BC%8C%E5%88%99-x%E7%9A%84%E7%AB%8B%E6%96%B9%2B2x%26%23178%3B%2B2009%E7%9A%84%E5%80%BC%E4%B8%BA%E5%A4%9A%E5%B0%91%EF%BC%9F%E8%A6%81%E8%BF%87%E7%A8%8B%EF%BC%81%EF%BC%81%EF%BC%81)
已知a-b=1,则a²-b²-2b的值为1.我要过程已知x²-x-1=0,则-x的立方+2x²+2009的值为多少?要过程!!!
已知a-b=1,则a²-b²-2b的值为1.我要过程
已知x²-x-1=0,则-x的立方+2x²+2009的值为多少?要过程!!!
已知a-b=1,则a²-b²-2b的值为1.我要过程已知x²-x-1=0,则-x的立方+2x²+2009的值为多少?要过程!!!
a-b=1,则a=b+1
a²-b²-2b
=(b+1)²-b²-2b
=b²+2b+1-b²-2b
=1
(2)
-x^3+2x²+2009
=-x^3+x²+x+x²-x-1+2010
=-x(x²-x-1)+(x²-x-1)+2010
=2010
a²-b²-2b=(a+b)(a-b)-2b=a+b-2b=a-b=1
a²-b²-2b=a²-(b²+2b+1)+1=a²-(b+1)²+1=(a+b+1)(a-b-1)+1=0+1=1;
x²-x=1;
-x³+2x²+2009
=-x²(x-1)+x²+2009
=-x+x²+2009
=1+2009<...
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a²-b²-2b=a²-(b²+2b+1)+1=a²-(b+1)²+1=(a+b+1)(a-b-1)+1=0+1=1;
x²-x=1;
-x³+2x²+2009
=-x²(x-1)+x²+2009
=-x+x²+2009
=1+2009
=2010
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