Solve x (x + 5) (x 4) < 0 for x.
Please show/tell how this was done, I must understand it!
Thanx a bunch!
2007-09-01 12:42:22 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
(x ? 4) should be (x - 4)
2007-09-01 12:57:55 · update #1
Hi,
This gives a cubic equation with zeros at x = -5, x = 0, and x = 4.
Since a cubic equation with a positive cubic term starts at the bottom on the left and goes up toward infinity on the right side, this graph follows this pattern:
The graph comes up from -infinity and crosses the x axis at x = -5. It is above the x axis until it turns back down and crosses the x axis again at x = 0. It loops below the x axis and bends back up to cross at x = 4. When x > 4, the graph is above the x axis and increasing towards infinity.
So x(x +5)(x - 4) < 0 when x < -5 and when 0 < x < 4.
Remember you can see this by entering Y1 = x(x +5)(x - 4) into a graphing calculator to see where the graph is lower than the x axis so that the y values are < 0.
I hope that helps!! :-)
2007-09-01 13:07:27 · answer #1 · answered by Pi R Squared 7 · 0⤊ 0⤋
This does not look like trig to me. What does (x ô 4) mean?
2007-09-01 19:48:33 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋