It is known that y is a positive proportional function of X. when the independent variable x increases by 5, the value of Y decreases by 7

It is known that y is a positive proportional function of X. when the independent variable x increases by 5, the value of Y decreases by 7

y=-(7/5)*x
The positive scaling function can be set as y = KX
According to the meaning of the question, k = - 7 / 5
So y = - (7 / 5) * x