F-r-e-e p-o-i-n-t-s for who is to answer first

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).

What term best describes a line ans a point that lie in the same plane

The final cost of a sale is determined by multiplying the price on the tag by 75%. which best describes the function that represents the situation?