A2 + b2 = c2 if a = 12 and c = 15, find the value of b using the pythagorean theorem. b = 399 b = 19.97 b = 81 b = 9

i am really confused and need

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%