Question

(с-1) (с+1)-(с+1) (с+2)

Answer 1

$(c-1)(c+1)-(c+1)(c+2)=c^2-1-(c^2+2c+c+2)= \ =c^2-1-(c^2+3c+2)= \ =c^2-1-c^2-3c-2=-3c-3$