Product of zeroes of a cubic polynomial is -d/a of cubic polynomial ax^3 + bx^2 + cx + d
So we know product of two zeroes therefore by putting value of product of two zeroes and taking third as a variable we get third zero as -2
Therefore -2 satisfies the equation and x+2 will be a factor of the equuation
By diving the above equation by x+2 we will get a quadratic rquation
I.e. x^2 -7x + 12
Now by splitting the middle term you can find the other two zeroes
i.e. x^2 - 4x -3x + 12
X(x - 4) -3(x - 4)
Therefore (x-3)(x-4)= x^2 - 4x -3x + 12
Therefore the other two zeroes are 3 and 4
The zetoes for the cubic equation are -2, 3 , 4
To verify you can put these values in the equation and find answer = 0