Answer :

Solution

- The solution steps are given below:

[tex]\begin{gathered} y\propto\frac{1}{x^2} \\ \\ \therefore y=\frac{k}{x^2} \\ where,\text{ }k\text{ is the constant of proportionality} \\ \\ when\text{ }x=1,y=\frac{7}{4} \\ \\ \frac{7}{4}=\frac{k}{1^2} \\ \\ \therefore k=\frac{7}{4} \\ \\ \text{ Thus, we can say} \\ y=\frac{7}{4x^2} \\ \\ \text{ Thus, when }x=3,\text{ we have:} \\ y=\frac{7}{4(3^2)} \\ \\ y=\frac{7}{4\times9} \\ \\ \therefore y=\frac{7}{36} \end{gathered}[/tex]

Final Answer

The answer is

[tex]y=\frac{7}{4x^2};y(3)=\frac{7}{36}\text{ \lparen OPTION C\rparen}[/tex]