a) x^2+x+16
б)с-100-1+2c=3c-101
в)(x-y)^2+x(y-x)=x^2-2xy+y^2+xy-x^2=xy+y^2=y(x-1)
г)a^2+2ab+b^2-2ab+2b^2=a^2+3b^2
