Polynomial root

The root of a polynomial f is a value for x where the polynomial value f(x) is zero.

For example, if the polynomial $f(x)=2x^{2}+10x-28$ then $f(2)=2\cdot 2^{2}+10\cdot 2-28=0$, so 2 is a root of this polynomial.

In fact, it can be seen that also -7 is a root of this polynomial.