Question 64321
The x intercept is where the value of y is 0 so you are trying to solve
{{{0 = x^3-2x^2-8x}}}
Factorise by taking out a common factor of x
{{{0 = x(x^2-2x-8)}}}
Factorise the trinomial by finding two numbers with a sum of -2 and a product of -8
{{{0 = x(x-4)(x+2)}}}
To get an answer of 0 one of the numbers multiplied together must be 0.
So either x = 0 or x-4=0 or x+2=0 
So the y intercepts are 0,4 and -2