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  • Użytkownik Zadane
2010-01-10T14:26:52+01:00
A) 14[(x2-2x+2)-3(-x2-x-2)]-(2x2-5x-6)= 14(x2-2x+2+3x2+3x+6)-(2x2-5x-6)= 14(4x2+x+2+3x2+3x+6)-(2x2-5x-6)= 14(4x2+x+8)-2x2+5x+6= 56x2+14x+112-2x2+5x+6= 54x2+19x+118

b)(x-2y)3-(x+y)3-(y-2x)3=
(x-2y)(x2+2xy+4y2)-(x+y)(x2-xy+y2)-(y-2x)(y2+4xy+4x2)=
(x3+2x2y+4x2y-2x2y-4x2y-8y3)-(x3-x2y+xy2+x2y-xy2+y3)- (y3+2xy2+8x2y-2xy2-4x2y-8x3)= (x3-8y3)-(x3+y3)-(y3+4x2y-8x3)=
x3-8y3-x3-y3-y3-4x2y+8x3=-10y3-4x2y+8x3