8)864 6)3810 9)5319 they’re all separate pls help

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?

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%

Write the equations in logarithmic form 9^4=6,561