Question

(1-2х)(4х2+2х+1)+8х ;
(2-х)(2+х)(х-1)+х2 (х-1) ;
(Х-5)2-4 (х+5)2 ;

Answer 1

$1)(1-2x)(4 x^{2} +2x+1)+8x=4 x^{2} +2x+1-8 x^{3} -4 x^{2} -2x= \\ =-8 x^{3} +1=1-8 x^{3}$

$2)(2-x)(2+x)(x-1)+ x^{2} (x-1)=(4- x^{2}+ x^{2} )(x-1)=4x-4$


$3)(x-5)^{2} -4 (x+5)^{2} = x^{2} -10x+25-4( x^{2} +10x+25)= \\ =x^{2} -10x+25-4 x^{2} -40x-100=-3 x^{2} -50x-75= \\= -3 x^{2} -45x-5x-75=-3x(x+15)-5(x+15)= \\ =(-3x-5)(x+15)$