Question

If $R=\left\{\right(x,y,)|x\in n,y\in n,x+3y=12\}$ then $R^{-1}$ is

• A. $\left\{\right(9,1),(2,6),(3,3\left)\right\}$
• B. $\left\{\right(3,1),(2,4),(3,6\left)\right\}$
• C. $\left\{\right(3,3),(2,6),(1,9\left)\right\}$
• D. $\left\{\right(1,3),(1,6),(1,9\left)\right\}$

Answer 1

The correct option is C $\left\{\right(3,3),(2,6),(1,9\left)\right\}$

Solution for the equation:
$x+3y=12$
is
$x=3,y=3$
$x=6,y=2$
$x=9,y=1$
Therefore,
$R=\{(3,3),(6,2),(9,1)\}$
$R^{-1}=\{(3,3),(2,6),(1,9)\}$