There is a basic property of numbers known as the zero product property.
If a product equals zero, then AT LEAST one of the factors must equal zero.
So if \(\displaystyle x(x - 1)(x + 2) = 0 \implies WHAT?\)
A common way to find the zeroes of a polynomial is to factor it. (The Fundamental Theorem of Algebra says that every polynomial of degree n > 2 and with real coefficients can be factored into polynomials of lower degree with real coefficients. Unfortunately, the theorem gives no guidance on how to do that factoring.)