consider
y = (x+17)(x-6)(x+14)
this cubic would have x-intercepts at
x = -17, -14, and 6
its first term is x^3, so it would rise in the 1st quadrant.
So the curve is above the x-axis, or positive for
-17 < x < -14 or x > 6
solve (x+17)(x-6)(x+14)>0
1 answer