Answer:
x=0 x=-5 x=2
Explanation:
4x3 + 12x2 = 40x
Subtract 40x from each side
4x3 + 12x2 - 40x=0
Factor out 4x from each term
4x( x^2 +3x-10) =0
Factor the term insdie the parentheses
What 2 numbers multiply to -10 and add to 3
5*-2 =-10
5+-2 =3
We have (x+5) (x-2)
Replace that in the equation
4x ( x+5) (x-2) =0
Using the zero product property
4x= 0 x+5 =0 x-2 =0
x=0 x=-5 x=2