Function or not a function¿

it is a function

Step-by-step explanation:

You just have to do y2-y1/x2-x1 and if you do everything for the first time you get 6/12 which is 2 and for the second one you get 6/12 which is 2 so it is a function

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: