Given the function $f : \mathbb{R}^2 \to \mathbb{R}^2$ as $f(x,y) = (x+3y,3x+y)$. Find $f^{-1}$ .( Assume $f$ is a bijection)
I know how to find $f^{-1} (x) = (3x+2)$ or anything with one variable. But I am not sure how to proceed with 2 variables. Can anyone provide me with a step by step explanation?
Thanks