1. [5] The graphs of the equations
$$
\begin{aligned}
y & =-x+8 \\
173 y & =-289 x+2021
\end{aligned}
$$
on the Cartesian plane intersect at $(a, b)$. Find $a+b$.
Answer: $\square$
Solution: From the first equation, it is known that $(a, b)$ lies on the line $x+y=8$, therefore $a+b=8$.