Having a problem with inverse proportion

[mc2_phy]

Reaaly need to solve these

 

[Saitama]

Hello mc2_phy, welcome to PF!

As per the rules, you need to show us your attempt before asking for help. :)

 

[mc2_phy]

I have attached a file of attempt :) Dont know how to find x

 

[Saitama]

I have attached a file of attempt :) Dont know how to find x

For which question have you posted this attempt?

Lets take the second for instance where b is inversely proportional to a^2.
We can write $b \propto \frac{1}{a^2}$. Removing the proportionality sign, $b =\frac{k}{a^2}$ where $k$ is some constant.
Substitute $a$ and $b$, find the value of k.