(а-4)^2-2a(3a-4)=(а-4)(а-4)-6а^2+8а=а^2-4а-4а+16-6а^2+8а=-5а^2+16
(a-4)^{2}-2a(3a-4)= a^{2}+16-(6a^{2}-8a)= a^{2}+16-6a^{2}+8a= 16-5a^{2}+8a
(а-4)^2-2a(3a-4)=(а-4)(а-4)-6а^2+8а=а^2-4а-4а+16-6а^2+8а=-5а^2+16
(a-4)^{2}-2a(3a-4)= a^{2}+16-(6a^{2}-8a)= a^{2}+16-6a^{2}+8a= 16-5a^{2}+8a