Amanda is 3 years older than Brantley and Carlos is twice as old as Amanda. The sum of their ages is 57. How old is Brantley?

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

Acredit card advertises an annual interest rate of 23%. what is the equivalent monthly interest rate?

Agroup of students want to create a garden. they do not know the exact measurements but they propose using a variable to represent the length and width of the garden. the length of the garden is 10 feet longer than double the width. use a single variable to write algebraic expressions for both the length and width of the garden. write an algebraic expression for the area of the garden. use mathematical terms to describe this expression.