Step-by-step explanation
1. Normalize to P(x)=0
Rewrite in standard form P(x)=0, then identify the leading and constant coefficients.
2. Test candidate roots
Build rational candidates from factor ratios p/q: -1, 1, -2, 2, -4, 4, -5, 5, -10, 10, -20, 20, -25, 25, -50, 50, -100, 100, -125, 125, -250, 250, -500, 500. Evaluate P(c) for each candidate and deflate when P(c)=0.
3. Solve the remaining factor
After deflation, solve the remaining factor using quadratic formula.
4. Collect all roots
All roots with multiplicity: x={-10,-10,5}.