Question

What is the value of class="latex-formula"> in this function?

Answer 1

Answer:

hello :

the graph passes by ( -4; 7/128)  : f(-4) = 7/128

a/ (-4)^4 = 7/128

a / 256 = 7/128

a/2 = 7

a = 14

Answer 2

We have the point:

$\left(-4,\ \dfrac{7}{128}\right)$

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

$f(x)=\dfrac{a}{x^4}\to y=\dfrac{a}{x^4}\\\\\left(-4,\ \dfrac{7}{128}\right)\to x=-4,\ y=\dfrac{7}{128}\\\\\dfrac{a}{(-4)^4}=\dfrac{7}{128}\\\\\dfrac{a}{256}=\dfrac{7}{128}\qquad\text{multiply both sides by 256}\\\\a=\dfrac{7}{128}\cdot256\\\\\boxed{a=14}$