[tex]▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪[/tex]
See the solution below ~
[tex] \large \boxed{ \mathfrak{Step\:\: By\:\:Step\:\:Explanation}}[/tex]
a.) The required expression is ~
here, k = proportionality constant ~
b.) Let's find the equation by Plugging the values as " x = 4 and y = 2 ~
now, the value of k can be determined ~
c.) find the value of x when y = 4 ~
Plugging the value of x as 4 and k as 50, we get ~
I hope it helped ~