Jude buys a book on sale for 30% off it’s original price b what expression represents the sale price of the book

Can someone answer it, and plot it, for 20 points and brainliest answer? p.s. they're the same ! : )

Which best explains why this triangle is or is not a right triangle ?

Sam opened a money-market account that pays 3% simple interest. he started the account with $7,000 and made no further deposits. when he closed the account, he had earned $420 in interest. how long did he keep his account open?