Question 135807
THE BEST WAY IS TO GRAPH THIS EQUATION THUS:
{{{ graph( 300, 200, -6, 5, -10, 10, -5x^2 +20x) }}} (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, -5x^2 +20x). 
THE ANSWERS ARE:(0,0) & (4,0) FOR THE 2 INTERSECTIONS WITH THE X AXIS.