e$)$ Let k$=1$ in the equilibrium equations in part d$)$ and show how the two equilibrium spending levels vary with changes in c $($that is$,$ interpret the signs of dx$/$dc and dy$/$dc$).$ Then let c $=1$ and show how the two equilibrium spending levels vary with changes in k $($that is$,$ interpret the signs of dx$/$dk and dy$/$dk$).$