Question

A merchant uses the rule: selling price equals cost + 10% of cost. This is a function. Why?

Answer 1

y=x+0.10

Explanation:

Answer 2

Let
x-------------> cost
y------------> selling price

we know that
y=x+0.10x-----------> y=1.10x

Is a function because, is a relation or correspondence between two magnitudes,x and y, so that each value of x corresponds to a single value of y.