Question

Номер 399,401,помогииитк

Answer 1

399)  $4a^2b^2+4ab+1= (2ab)^2+2*2ab+1=(2ab+1)^2$

$1-xy+ frac{x^2y^2}{4}=1-2* frac{1}{2}xy+( frac{xy}{2})^2=(1- frac{xy}{2})^2$

401)

$12a^3x-36a^2bx+27ab^2x=3ax(4a^2-12ab+9b^2)=3ax(2a+3b)^2$

$2a^2b^3-28ab^2+98b=2b(a^2b^2-14ab+49)=2b(ab-7)^2$