It's almost New Year, and we want to surprise our math teacher. $2020$ is coming, and we want to wish her a Happy New Year in an interesting way. We have studied systems of linear equations and want to think of a system with solution $x=20$ and $y=20$. It must be a system of linear equations because of the only solution that we want.
$\begin{array}{|l} a_1x+b_1y=d_1 \\ a_2x+b_2y=d_2 \end{array}$
I am not sure how to approach the problem. We haven't studied square matrices or the Cramer's rule. We've studied the Graphic method, the Substitution method, and the Elimination method.
Pick the coefficients $a_1,b_1,a_2,b_2$ that you like, and compute
$$d_1=20a_1+20b_1,\\d_2=20a_2+20b_2.$$