Question

Помогите пж решить примери.Фото

Answer 1

Держи.’вджудазужсзыы

Answer 2

$\boxed{(a-b)(a+b)=a^2-b^2}$

$1)~(a+5)(a-5)=a^2-5^2=a^2-25\\\\2)~(4+x)(x-4)=(x+4)(x-4)=x^2-4^2=x^2-16\\\\3)~(2a-7)(2a+7)=(2a)^2-7^2=2^2a^2-49=4a^2-49\\\\4)~(12x+13y)(13y-12x)=(13y+12x)(13y-12x)=\\\\=(13y)^2-(12x)^2=13^2y^2-12^2x^2=169y^2-144x^2\\\\5)~(a^3-b^4)(a^3+b^4)=(a^3)^2-(b^4)^2=a^{3\cdot2}-b^{4\cdot2}=a^6-b^8$

$6)~\bigg(10x^3y-\dfrac{1}{9}xy^2\bigg)\bigg(10x^3y+\dfrac{1}{9}xy^2\bigg)=(10x^3y)^2-\bigg(\dfrac{1}{9}xy^2\bigg)^2=\\\\=10^2x^{3\cdot2}y^2-\bigg(\dfrac{1}{9}\bigg)^2x^2y^{2\cdot2}=100x^6y^2-\dfrac{1^2}{9^2}x^2y^4=100x^6y^2-\dfrac{1}{81}x^2y^4\\\\7)~(0,4m^5+0,1n^3)(0,1n^3-0,4m^5)=(0,1n^3+0,4m^5)(0,1n^3-0,4m^5)=\\\\=(0,1n^3)^2-(0,4m^5)^2=0,1^2n^{3\cdot2}-0,4^2m^{5\cdot2}=0,01n^6-0,16m^{10}$