Nine friends share 5 brownies evenly how much does each friend get?

Find the gradient of f(x,y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

Icould really use some with this question.

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.