$1.$ Consider the following.

$(a)$ Find the least squares regression line.

$y=$

$(b)$ Calculate $S,$ the sum $of$ the squared errors. Use the regression capabilities $of$ a graphing utility $to$ verify your results.

$2.$ Find all relative extrema and saddle points $of$ the function. Use the Second Partials Test where applicable. $(Ifan$ answer does not exist, enter DNE.$)$

$3.$ Use a computer algebra system $to$ graph the surface and locate any relative extrema and saddle points. $(Ifan$ answer does not exist, enter DNE.$)$

$z=\frac{-8x}{x^2+y^2+1}$

relative minimum $,(x,y,z)=(,)$

relative maximum $,(x,y,z)=(,)$

saddle point $,(x,y,z)=(,)$