=(a-2a)+(3a-4a)+(5a-6a)+.(2009a-2010a)
=(-a)*(2010/2)
=-1005a
2x方-5x=0
2x方=5x
(15x方-18x+9)-(-3x方+19x-31)-8x=18x方-45x+40
=9*(2x方)-45x+40
=9*(5x)-45x+40
=40
=(a-2a)+(3a-4a)+(5a-6a)+.(2009a-2010a)
=(-a)*(2010/2)
=-1005a
2x方-5x=0
2x方=5x
(15x方-18x+9)-(-3x方+19x-31)-8x=18x方-45x+40
=9*(2x方)-45x+40
=9*(5x)-45x+40
=40