Importance of 10

Algebra Level 4

Let $$\displaystyle f(x) = (1 - a) x^2 + (1 + ab - b) x + 1 + b^2,$$ where $$a$$ and $$b$$ are single-digit natural numbers. Given that one of the roots of $$f(x)$$ is $$10,$$ find the other root.

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