Question

What is the value of $a$ ?

Answer 1

Answer:

hello :

the graph passes by ( 3; -1/3)  : f(3) = -1/3

a/ (3)^3 = -1/3

a / 27 = -1/3

a/9 = - 1

a = - 9

Answer 2

We have the point:

$\left(3,\ -\dfrac{1}{3}\right)$

Put the coordinates of the point to the equation of the function f:

$f(x)=\dfrac{a}{x^3}\to y=\dfrac{a}{x^3}\\\\\left(3,\ -\dfrac{1}{3}\right)\to x=3,\ y=-\dfrac{1}{3}\\\\\dfrac{a}{3^3}=-\dfrac{1}{3}\\\\\dfrac{a}{27}=-\dfrac{1}{3}\qquad\text{multiply both sides by 27}\\\\a=-\dfrac{1}{3}\cdot27\\\\\boxed{a=-9}$