(1)x 2+2px+1=[x 2+2px+(p 2)]+(1-p 2)=(x+p) 2+( 1-p 2);
故答案为p 2;1-p 2;p;1-p 2;
(2)a 2-b 2+4a+2b+3,
=(a 2+4a+4)-(b 2-2b+1),
=(a+2) 2-(b-1) 2,
=(a+2+b-1)(a+2-b+1),
=(a+b+1)(a-b+3).
故答案为:(a+b+1)(a-b+3).
(1)x 2+2px+1=[x 2+2px+(p 2)]+(1-p 2)=(x+p) 2+( 1-p 2);
故答案为p 2;1-p 2;p;1-p 2;
(2)a 2-b 2+4a+2b+3,
=(a 2+4a+4)-(b 2-2b+1),
=(a+2) 2-(b-1) 2,
=(a+2+b-1)(a+2-b+1),
=(a+b+1)(a-b+3).
故答案为:(a+b+1)(a-b+3).