How can you tell if a relation is a function

One way to tell if a relation is a function is by using something called the vertical line test. In other words, if we can draw a vertical that passes through more than one point on a graph, then the relation does not represent a function. Another way to tell if a relation represents a function is by looking at the X coordinates of each ordered pair. If any of the ordered pairs have the same X coordinate, then the relation is not a function.

the perimeter is increased by a factor of 2

hello :

by applying the distributive property :

6 × 4.3 = 6 × ( 4 + 0.3 )

            =   (6 ×   4) + (6 ×   0.3)

            = 24 + 1.8

6 × 4.3 = 25.8