Round 8,373 to the nearest thousand

In a school 2/3 of the students study a language of those who study a language 2/5 study french

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).

Evaluate-27 ^4/3/8 a) - 81/16 b) 81/16 c) 16/81