Ajeweler orders necklaces from a website that offers $6 shipping for any-size order. each necklace costs $7. the jeweler wants to know the total cost of ordering n necklaces. what is the independent (input) variable?

You can use the definition of independent variable to find which variable is independent in the given situation.

The variable n (the number of necklace) is the independent (input) variable.

The variable which is not dependent on other variables in the given context for its values is called independent variable.

When we give input to a function, generally it is independent variable. The variable which depends on the other variable is called dependent variable.

Mostly, we will find that dependent variables are output of functions of independent variables. But it is not necessary for dependent variables.

Since the number of necklace brought here is not depending on other variables like cost etc, and it is used for calculating cost, thus n (number of necklace brought) is input variable and is independent variable in this context.

The cost calculated is dependent on the number of necklace brought. The more value of n is, the more cost will have to be paid.

Cost = Tax  + $7 times number of necklace

c = 6 + 7n

Thus,

The variable n (the number of necklace) is the independent (input) variable.

Learn more about independent variable and dependent variable:

link

the answer, i believe is y-8=1(x+4)