8. Given the line $l: 2 x+y=10$, draw a line $l^{\prime} \perp l$ through the point $(-10,0)$, the coordinates of the intersection point of $l^{\prime}$ and $l$ are
$l^{\prime}: x-2 y+10=0$, solving $\left\{\begin{array}{l}2 x+y-10=0, \\ x-2 y+10=0\end{array} \Rightarrow\left\{\begin{array}{l}x=2, \\ y=6 .\end{array}\right.\right.$
Therefore, the intersection point of $l^{\prime}$ and $l$ is $(2,6)$.