Question

(x+2) and(x-3) are factors of x^3+ax+b,find a,b and factorise eq.

Answer 1

If (x+1) and (x+2) are the factors of x^3+3x^3-3ax+b, then what is a and b?

I am not sure if you asked the question you wanted. You wrote x^3+3x^3-3ax+b, but I think you meant x^3+3x^2-3ax+b.

I will answer the question you wrote: x^3+3x^3-3ax+b

4x^3-3ax+b=0 Equation 1

x+1=0, x=-1

x+2=0, x=-2

If x=-1 enter -1 into equation 1 to get -4+3a+b=0

if x=-2 enter -2 into equation 1 to get -32+6a+b=0

Substract the two new equations to get 28–3a=0

a=28/3

Enter a into equation 1 with x=-1 to get -4+3*28/3+b=0

b=-28+4=-24