Please help i don't understand it

Which of these tables represents a non-linear function?

The square root of 9x plus 7 plus the square rot of 2x equall to 7

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.