Use synthetic division to find out the remaining quadratic:
]]>x³-9-6x=0
(x³-27)+18-6x=0
(x-3)(x²+27x+27²)-6(x-3)=0
(x-3)(x²+27x+723)=0
x-3=0
x=3
and
x²+27x+723=0
D<0 no solutions
Now the answer is correct.
Could u explain me how you get this (x^2+3*x+3)?
]]>We can factor out (x-3) from here, leaving
(x-3)(x^2+3*x+3) = 0
x-3 = 0, so x=3 is a solution
x^2 + 3x + 3 = 0
This can be solved easily using the quadratic formula
x³=6x+9
It doesn't seem difficult, but my answer doesn't suit to the answer in the book
]]>