а³+21а²+147а-7=а³+3*7*а²+3*а*7²-7+7³-7³=
=(а³+3*7*а²+3*а*7²+7³)-7-7³=
=(а+7)³-7-343=
=(а+7)³-350
При а=∛7-7 имеем (∛7-7+7)³-350=7-350= =-343
Copyright © 2024 SCHOLAR.TIPS - All rights reserved.
Answers & Comments
а³+21а²+147а-7=а³+3*7*а²+3*а*7²-7+7³-7³=
=(а³+3*7*а²+3*а*7²+7³)-7-7³=
=(а+7)³-7-343=
=(а+7)³-350
При а=∛7-7 имеем (∛7-7+7)³-350=7-350= =-343