Can you find a factor of -30 that makes this expression equal 0?
It doesn't factorise.
A sketch graph shows that there is a single real root to the right of x = 4,
and a table of values narrows it to between x = 5 and x = 6.
You can get a better approximation if you wish, but you are then into your favourite numerical method.
Help! .How to factorise:
According to the key, 2 roots are imaginary and 1 root is real.
It is not factorable.
The only possible rational roots are: .
. . None of them are zeros of the polynomial.
We find that: .
Hence, there is a root (irrational) on the interval
Another possibility: a typo in the problem.
. . Could the constant term be -20 or -36?