Fill in each blank with the appropriate response.

Question

The graph of y = -10|x| can be obtained from the graph of y = |x| by vertically stretching by a factor of___ and reflecting across the__-axis.

Answer 1

The -10 in front of the |x| does two things.  First, it makes all the y values ten times greater than just |x| alone; hence it stretches the values by a factor of 10.   For example, if x=-2, |-2| = 2, but -10|-2| = -20, ten times more.  Second, it makes the y values negative instead of positive.  Hence the negative sign reflects the values across the x-axis.