Which number must replace the [?] so that this equation has infinitely many solutions? 3(5x + [?]) = 8z + 15 + 72 - 6
1. 3
2. 9
3. -3
4. -9

Aaron invested a total of $4,100, some in an account earning 8% simple interest, and the rest in an account earning 5% simple interest. how much did he invest in each account if after one year he earned $211 in interest? select one: a. $200 at 8%, $3,900 at 5% b. $3,200 at 8%, $900 at 5% c. $900 at 8%, $3,200 at 5% d. $3,900 at 8%, $200 at 5%