1)(a+7)(a-7)=a^2-7a+7a-49=a^2-49.
2)(6+x)(x-6)=6x-36+x^2-6x=-36-x^2.
3)(4b-1)(4b+1)=16b+4b-4b-1=16b-1.
4)(8m+3y)(3y-8m)=24my-64m^2+3y^2-24ym=-64m^2=3y^2.
5)(x^7-q^5)(x^7+q^5)=x^14+x^7q^5-q^5x^7-q^10=x^14-q^10.
6)(7a^2Y3-1/5ay^2)(7a^2Y^3+1/5ay^2)=49a^4y^6+7/5a^3y^5-7/5a^3y^5-7/5a^3y^5-2/10a^2y^4=49a^4y^6-2/10a^2y^4.
7) (0,3p^3+0,2q^4)(0,3p^3-0,2q^8)=0,09p^6-0,05p^3q^4+0,05q^4p^3-0,04q^8=0,09p^6-0,04q^8.
8)Не знаю
9) (m^6-n^5)(-m^6-n^5)=-m^12-m^6n^5+n^5m^6+n^10=-m^12+n^10.
10) (1,3a^11+2/9b^3)(2/9b^3-1,3a^11)=13/45a^11b^3-1,69a^22+4/18b^6-13/45b^3a^11=-1,69a622+4/18b^6.
№3
6(7x-3)-8(4x+2)+2(5-3x)=3
42x-18-32x-16+10-6x=3
42x-32x-6x-18-16+10=3
4x-24=3
4x=-21
x=-21:4
x=5.25
Ответ: 5,25