(a+b+2)(a+b)-(a-b)^2+1 = a^2 +2ab + b^2 +2a +2b - (a^2 -2ab +b^2) +1 =
a^2 +2ab + b^2 +2a +2b - a^2 + 2ab - b^2 +1 = 4ab + 2a + 2b +1 = 2a(2b+1) + 2b +1 =
(2b+1)(2a+1)
(a+b+2)(a+b)-(a-b)^2+1 = a^2 +2ab + b^2 +2a +2b - (a^2 -2ab +b^2) +1 =
a^2 +2ab + b^2 +2a +2b - a^2 + 2ab - b^2 +1 = 4ab + 2a + 2b +1 = 2a(2b+1) + 2b +1 =
(2b+1)(2a+1)