Վարժ․127

ա/(a+1)(a+1)(a+1)=a3+3a2+3a+1

բ/(x-1)(x-1)(x-1)=(x2-x-x+1)(x-1)=x3-x2-x2+x=x3-3x2+3x-1

գ/(a+b)(a-b)(a+b)=(a2-ab-ba-b2)(a+b)=a3+a2b-a2b-ab2-ba2-b2a-b3=a3-a2b-3b2a-b3

դ/(m-n)(m-n)(m+n)=(m+n)*(m2-2mn-n2)=m3-2m2n-mn2nm2-2mn2-n3=m3-m2n-3mn2-n3

ե/(a+b+c)(a+1)=(a+1)(a+b+c)=a2+ab+ac+a+b+c

զ/(a-b-c)(a-1)=(a-1)(a-b-c)=a2-ab-ac+a+b+c

է/(x+1)(x2-x+1)=x3-x2+x+x2-x+1=x3+1

ը/(x-1)(x2+x+1)=x3+x2+x-x2-x-1=x3-1

թ/(x3+2x-3)(2-3x)=(2-3x)(x3+2x-3)=2x3+4x-6-3x4-6x2+9x= -3x4+2x3-6x2+13x-6

ժ/(5m2-3mn+n2)(2n-m2)=10m2n-5m4-6mn2+3m3n+2n3-m2n2

ի/(a+b+c)(a+b-c)=a2+ab-ac+ab+b2-bc+ac+bc-c2=a2+b2-c2+2ab

լ/(a-b+c)(a-b-c)=a2-ab-ac-ab+b2+bc+ac-cb-c2=a2+b2-c2-2ab

Վարժ․128

ա/-(a+b)(a+b)=a2+ab+ba+b2=a2+2ab+b2= -a2-2ab-b2

բ/-(x-y)(x+y)= -x2+xy-yx-y2= -x2+y2

գ/-(x-y)(x-y)= -x2-xy-yx+y2= -x2-y22xy

դ/-(2m-n)(n-3m)= -(2mn-6m2-n2+3mn)= -5mn+6m2+n2

ե/-(5a-2b)(3b+2a)= -(15ab+10a2-6b2-4ab)= -11ab-10a2+6b2

զ/-7(x+8y)(y-3x)= -7(xy-3x2+8y2-24xy)= -7(8y2-3x2-23xy)= -56y2+21x2+161xy