please dont dont use al to solve this.

Q$.1$ Determine which of the given relations $R$ are functions with domain $x$ :

$($a$)x=\{1,3,5,7,8\}$ and $R=\{(1,7),(3,5),(5,3),(7,7),(8,5)\}$

$($b$)x=\{0,1,2,3\}$ and $R=\{(0,0),(1,1),(1,-1),(2,2),(3,-3)\}$

Q$.2$ Find $f$@$g$ for the functions $f(x)$ and $g(x)$ :

$($a$)g(x)=\sqrt[\phantom{2}]{2x-5},f(x)=5x^2-3$

$($b$)g(x)=\sqrt[3]{x-4},f(x)=x^3+4$

$($c$)f(x)=si{n}^{3}x,g(x)=x+2$