Question

Помогите с 1 заданием СРОЧНО!!)

Answer 1

1) 1+a-a-a^2 =1-a^2

3)m^2+mn-mn+n^2=m^2+n^2

5) 6ab -9a^2 +4b^2 -6ab = -9a^2 +4b^2

2) b^2-2b+2b-4=b^2-4

4) x^2-xy +xy-y^2=x^2-y^2

6) 15ab +9b^2 - 25a^2 -15ab = 9b^2 - 25a^2

Answer 2

(1-a)(1+a)=1+a-a-a^2=a^2-1
(b+2)(b-2)=b^2-2b+2b-4=b^2-4
(m-n)(m+n)=m^2+mn-mn-n^2=m^2-n^2
(x+y)(x-y)=x^2-ху+ху-у^2=х^2-у^2
(3a+2b)(2b-3a)=6ab-9a^2+4b^2-6ab=-9a^2+4b^2
(3b-5a)(5a+3b)=15ab+9b^2-25a^2-15ab=-25a^2+9b^2