Упростите Выражение: 1) 5a (a-8)-3 (a+2) (a-2)             2) (1-4b) (4b+1)+6b (b-2)             3)(8p-q) (q+8p)-(p+q) (p-q)        4) (2x-7y) (2x+7y) + (2x-7y) (7y-2x)

1)5a(a-8)-3(a+2)(a-2)=[latex]=5a^{2}-8-3(a^{2}-4)=5a^{2}-8-3a^{2}+12=\\=2a^{2}+4=2(a^{2}+2)[/latex]   2) [latex](1-4b)(4b+1)+6b(b-2)=1-16b^{2}+6b^{2}-12b=-10b^{2}-12b+1[/latex]  3)[latex](8p-q)(q+8p)-(p+q)(p-q)=64p^{2}-q^{2}-(p^{2}-q^{2})=63p^{2}[/latex] 4) [latex](2x-7y)(2x+7y)+(2x-7y)(7y-2x)=4x^{2}-49y^{2}-(2x-7y)^{2}=\\=4x^{2}-49y^{2}-(4x^{2}-28xy+49y^{2})=\\=-49y^{2}+28xy-49y^{2}=28xy-98y^{2}=2y(14x-49y)[/latex]