Answer: y= 15x represents a proportional relationship.
Explanation:
A proportional relationship is one in which two quantities vary directly with respect to each other.
That is, We can say the variable varies directly as if: y = k x. for some constant , which is called the constant of proportionality .
Or we can say that the graph of the function that describes proportional relationship must passes through the origin.
And, It will show the proportional change ( that is, if x increases y increases and if x decreases y decreases)
Since,In Option A) y=-5(x+1) if x increases y will decreases therefore it is not a proportional relationship.
In Option B) y = 5x + 1 since, the graph of this not passing through the origin therefore, it is not a proportional relationship.
In Option C) y=-x , if x increases y will decreases therefore it is not a proportional relationship.
In Option D) y=15x, The graph is passing through the origin also if x increses y will also increase therefore, It is proportional relationship.