Question

a×(a+2)+b×(b+2)-2×(a+1)×(b+1)+1

Answer 1

${a}^{2} + 2a + {b}^{2} + 2b - 2(ab + a + b + 1) + 1 = {a}^{2} + 2a + {b}^{2} + 2b - 2ab - 2a - 2b - 1 + 1 = {a}^{2} + {b}^{2} - 2ab$