Question number 8.
Given: xy + 10y$^2$ = -9. Use implicit differentiation to find all points where the tangent line to this curve is vertical.
($6\sqrt{10}, -\frac{9}{10}$) and ($-6\sqrt{10}, -\frac{9}{10}$)
($2\sqrt{30}, -\frac{3}{10}$) and ($-2\sqrt{30}, -\frac{3}{10}$)
($-2\sqrt{10}, -\frac{9}{10}$) and ($2\sqrt{10}, -\frac{9}{10}$)
($-2\sqrt{30}, -\frac{3}{10}$) and ($2\sqrt{30}, -\frac{3}{10}$)
($-6\sqrt{10}, -\frac{9}{10}$) and ($6\sqrt{10}, -\frac{9}{10}$)
None of the above.