Question

Which of the following represents a non-proportional function? X -5 y -5.5 -1.5 -1 4.5 4 8 7.5 o {(-1, 1), (2,-2), (3, -3), (5, -5)} y = 2

Answer 1

A proportional function has the form:

$y\text{ = k }\cdot\text{ x}$

where k is a constant.

So, option 1 it is a proportional function, because it's a straight line crossing from zero.

Option 2 is non-proportional function because:

$\frac{-5.5}{-5}\ne\text{ }\frac{-1}{-1.5}$

Option 3 is proportional function:

$\frac{1}{-1}=\frac{-2}{2}=\frac{-3}{3}=\frac{-5}{5}$

Option 4 is proportional function, because has the form I mention above.

The correct answer is Option 2.