Evaluate the algebraic expression 25/r-4 if r=9

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

What is fraction that is equivalent to 3/8