1)(7x-2)^2+28x
(3x+1)^2-21x
2)a^3+2a+a^2+2

1)(7х-2)^2+28х=49х^2-28х+4+28х=49х^2+4(3х+1)^2-21х=9х^2+6х+1-21х=9х^2-15х+12)а^3+2а+а^2+2=а(а^2+2)+а^2+2=(а^2+2)(а+1)