\[\boxed{\text{631\ (631).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[1)\ n² + 60n + \ * = (* + 30)^{2},\ \ \]
\[2)\ 25c² - \ *\ + *\ = (*\ - \ 8k)^{2},\ \ \]
\[3)\ 225a² - \ *\ + 64b^{4} = (*\ - \ *)^{2},\ \ \]
\[4)\ 0,04x² + \ *\ + * = (*\ + 0,3y^{3})²\]