Calculate ${\mathbf{T}}_u$, ${\mathbf{T}}_v$, and $\mathbf{n}(u,v)$ for the parametrized surface at the given point.
Then find the equation of the tangent plane to the surface at that point.

$\Phi(u,v)= (2u+v,u-4v,2 u)$;$\qquad u=8\text{,}\quad v=9$

${\mathbf{T}}_u=$ , ${\mathbf{T}}_v=$ , $\mathbf{n}(u,v)=$

The tangent plane:
$=9z$