5x+y=-1 and y-4x=3 solve by substitution

Which of the following is the inverse of y = 3∧x y = 1/3∧x y = ㏒3x y = (1/3) ∧x y = ㏒ 1/3∧x

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.

The high temp today was 62°. when nighttime comes, the temp will drop 40°. by 4am the temp will drop an additional 40°. what is the temp at 4am?