Indicate functions that are directly proportional y = 0.3 y = -8x ^ 3 y = x / 4 y = 7 / x

Let’s consider each function and find the directly proportional one.

Before that, we write down the general formula of a directly proportional function: y = k * x, where x is an independent argument, y is a function, and k is some constant coefficient.

1) y = 0.3, here y does not depend on the argument x, but is equal to the constant 0.3;

2) y = -8x ^ 3, this is a cubic dependence, not directly proportional;

3) y = x / 4 = (1/4) * x, here the dependence is directly proportional, where k = 1/4, and with an increase (decrease) x y also increases (decreases);

4) y = 7 / x, here the inverse dependence of y on x, since x is in the denominator.

Answer: 3) y = x / 4.