(3+х)²=(х+3)(х-3)
3×3+х×3+х×3+х×х=х×х+3×х-3×х-3×3
9+3х+3х+х²=х²+3х-3х-9
9+6х+х²=х²-9
9+6х=-9
-9-9=6х
-18=6х
х=-3
ответ: х=-3
(3+х)²=(х+3)(х-3)
3×3+х×3+х×3+х×х=х×х+3×х-3×х-3×3
9+3х+3х+х²=х²+3х-3х-9
9+6х+х²=х²-9
9+6х=-9
-9-9=6х
-18=6х
х=-3
ответ: х=-3