If ab = 0, then a = 0 or b = 0. After you factor, set each factor equal to zero. Factoring as a set is in factoring quadratics.
Factor, then split
(x − 3)(x + 5) = 0 gives x = 3 or x = −5. Interval notation is how some answers write the leftover set, in interval notation. Polynomials as a set are in polynomials.
The bottom line
Product zero means a factor is zero. Do not divide both sides by a variable and lose a root.
Start practicing
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