The value of a textbook is $61 and decreases at a rate of 15% per year for 14 years.

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).

Solve 3x-18=2y and 5x-6y=6 by elimination show work

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?