Consider the following$\mathrm{.}2($x $-6)2($y $-9)2(2-4)?=10,(7,11,6)($a$)$ Find an equation of the tangent plane to the given surface at the specified point.$($b$)$ Find an equation of the normal line to the given surface at the specified point.$($x$($t$),$ Y$($t$),$ z$($t$))=$