$[-/0\mathrm{.}59$ Points$]$

SCALCET$914.$XP$\mathrm{.}6\mathrm{.}014.$

Find the directional derivative of the function at the given point in the direction of the vector $v.$

$,g(x,y,z)=(x+2y+3z{)}^{\frac{3}{2}},(4,3,5),v=4j-k$

$D_{u}g(4,3,5)=$

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$17.[-/0\mathrm{.}58$ Points$]$ SCALCET$914.$XP$\mathrm{.}6\mathrm{.}026.$

Consider the following.

$yz=8ln(x+z),(0,0,1)$

$($a$)$ Find an equation of the tangent plane to the given surface at the specified point.

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$($b$)$ Find an equation of the normal line to the given surface at the specified point.

$(x(t),y(t),z(t))=()$

HELP WITH BOTH $16$ and $17$ PLEASE