Past exam of the mathematics course of the year 1 of the natural sciences course of the University of Cambridge / 2005 / Paper 2 / 6 / b

The coefficient vector $\mathbf{n}=(1,2,2)$ is a normal vector, so a vector equation of the plane isA parametric version is $\mathbf{r}=(20,0,0)+s(-2,1,0)+t(-2,0,1)$, since both independent direction vectors are perpendicular to $\mathbf{n}$.