Răspuns :
a) (x-a) ( x+a)
(x-5)(x+5)
(x-3)(x+3)
(1-2x)(1+2x)
(x-1)(x+1)
b) (x-1)(x+1)
(x-4)(x+4)
(2-x)(2+x)
(x-3)(x+3)
-(x-9)(x+9)
c) (x-5)(x+5)
(x-9)(x+9)
(x-7)(x+7)
(7-x)(7+x)
(x-5)(x+5)
(x-3)(x+3)
(1-2x)(1+2x)
(x-1)(x+1)
b) (x-1)(x+1)
(x-4)(x+4)
(2-x)(2+x)
(x-3)(x+3)
-(x-9)(x+9)
c) (x-5)(x+5)
(x-9)(x+9)
(x-7)(x+7)
(7-x)(7+x)
(x-a)(x+a)
(x-5)(x+5)
(x-3)(x+3)
(1-2x)(1+2x)
(x-1)(x+1)
(x-5)(x+5)
(x-3)(x+3)
(1-2x)(1+2x)
(x-1)(x+1)