Answer
a) slope at $x=-3$ is greater.
b) $(-2, 3)$ and $(2, 3)$.
c) $(0, 5.8)$.
Work Step by Step
a) The greater the slope, the closer the line is to the vertical. The tangent at $x=-3$ is closer to the vertical than the tangent at $x=-1.$
b) Visually, the graph has a vertical tangent at $x=-2$ and $x=2$; checking the y-values at these points gives us the points' coordinates.
c) Visually, the graph has a horizontal tangent at $x=0$; estimating the y-value at that point gives us the point's coordinates.