Номер

A)25 - 36pc=5 - 6pc=(5-6pc)(5+6pc)
б)(3х+1)-(4х+3)= (3х + 1 -(4х+3))(3х+1+4х+3) =
=(3х+1-4х-3)(7х+4) = (-х-2)(7х+4) = -(х+2)(7х+4)
в)х - 9 = х - 3 = (х-3)(х+3)
г)2а(5а-10)+(2а-8)(3а+2) = 10а -20а  + 6а-24а+4а-16 =
= 16а -40а -16 = 8(2а-5а -2)
д)(3х-5)(4х-5) -2х(2,5+1,5) = 12х -15х -20х +25  - 2х *4=
=12х - 35х + 25 - 8х = 12х -43х +25  (???)
е)100аbc  - 121 = 10(a)bc - 11 = (10abc -11)(10abc+11)
ж)(а+b+c)-(a-b-c) =(a+b+c  -(a-b-c))(a+b+c +a-b-c) =
= (a+b+c-a+b+c)*2a = 2a(2b+2c) = 2a*2(b+c) = 4a(b+c) 
з)81a  - 1 = (3a)  - 1 = (3a -1)(3a +1) = (3a-1)(3a+1)(9a+1)

2.
а)3a-6аb-3b=-3(a+2ab+b) = -3(a+b)
б)ах+4ах +4а =а(х+4х +4)= а(х +2*2х +2)=а(х+2)
в)-5а-10аb-5b = -5(a+2ab+b)= -5(a+b)
г)-3х+12х-12 =-3(х - 4х + 4) = -3(х -2*2х +2) = - 3(х-2)
д)аb-4abc+4bc = b(a-4ac +4c) = b(a-2*a*2c +(2c) ) = b(a-2c)
е)2х-4х + 2 = 2(х -2х +1) = 2(x-x  -x+1) = 2(x(x-1) -(x-1)) =
= 2 (x(x-1)(x+1) - 1(x-1) ) = 2 (x-1)(x(x+1) - 1)  =
= 2(x-1)(x+x-1)
з)-12х-12х-3х = -3х(4х +4х + 1) =-3x((2x)+2*2x*1 +1)= -3x(2x+1)