Question

Воспользуйтесь формулой:

Answer 1

=1+2c+c^2+2d+2cd+d^2

Answer 2

$(1+c+d)^{2}=(1+c) ^{2}+2*(1+c)*d+ d^{2}=1+2c+ c^{2} +2d+2cd+d^{2}$