an equation I cant seem to figure out if you could provide a step by step solution that would be helpful

What is the value of x in the diagram below?

Solve for n? [tex]z = \frac{3}{4} mn[/tex]

Ebuka's monthly rent is $750. if ebuka pays the rent late, his landlord charges 4% interest per week that the payment is late. write a function that gives the total cost r(t), in dollars, of ebuka's rent if he pays it t weeks late.