### Video Transcript

For the given graph, estimate ๐
prime of negative 1.5.

Letโs mark on the graph the point
where ๐ฅ equals negative 1.5. And we want the value of the
derivative at this point. Letโs recall that the derivative ๐
prime of ๐ฅ is the slope of the tangent line to the graph at the point ๐ฅ. So, letโs try and draw on the
tangent line at our point.

We want to draw a line that follows
the general direction of the curve at the point negative 1.5. It would look something like
this. Itโs a horizontal tangent line. This means that at our point
negative 1.5, the derivative is zero. And so, we can estimate that the
value of ๐ prime of negative 1.5 is zero.