Question

A direct variation function contains the points (-9, -3) and (-12, -4). Which equation represents the function?

y = -3x
y=-
o ya
y = 3x

Answer 1

`y=(1)/(3) x`

Explanation:

we need a function that when we plug the value of x, we get the given value of y.

In the coordinate point

(-9, -3)

the x and y values are:

x = -9

y = -3

so we can see that the value of y is one third of the x value (because -9/3 = -3):

`y=(1)/(3) x`

this is also true for the secod point:

(-12, -4)

here the x and y values are:

x = -12

y = -4

again the y value is one third of the x value (because -12/3 = -4):

`y=(1)/(3) x` ⇒ this is the equation that represents the function.