Wha is nine less than an unknown number equals 15

G(x)=x2-16xb=-16, so =16 = 649(x) = (x2 - 16x + 64) - 649(x) = (x - 1)2-

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

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?