solve the inequality for x

x^3-5x greater then or equal to 4x^2
i simplified to x(x+5)(x-1) but its saying that is incorrect

Question

solve the inequality for x

x^3-5x greater then or equal to 4x^2
i simplified to x(x+5)(x-1) but its saying that is incorrect

anonymous · Answer

$$x^{3}-5x \ge 4x ^{2}$$

anonymous · Answer

I'm solving hold on

anonymous · Answer

i figured it out and its $$x(x-5)(x+1)$$ how do i figure out which are included in the solution set

anonymous · Answer

$$x^3-5x\geq 4x^2$$

$$x^3-4x^2-5x\geq0$$
$$x(x^2-4x-5)\geq 0$$
$$x(x+4)(x-5)\geq0$$ 
zeros are at -4, 0  and 5and since this is a cubic polynomial with positive leading coefficient, it will be negative, then positive, then negative, then positive (think of the picture)
you want it to be positive, so answer is 
$$[-4,0]\cup [5,\infty)$$

anonymous · Answer

in your head draw this picture |dw:1314549885298:dw|

anonymous · Answer

it says the answer is (-1,0] U [5, infinity)

anonymous · Answer

because if you factor out (x+4)(x-5) you get $$x ^{2}-1x-30$$ which  isnt what i want

anonymous · Answer

solution
x>=5
-1<=x<=0