Answer:
A| 12, 3
Step-by-step explanation:
The polynomial can be factored by looking for factors of 36 that sum to -15. The sum being negative while the product is positive means both factors will be negative. The answer choices suggest ...
y = (x -12)(x -3)
A quick check shows this product is ...
y = x^2 -12x -3x +36 = x^2 -15x +36 . . . . as required
The factors are zero when x is either 12 or 3.
The zeros of the equation are 12 and 3.
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Once you realize the constants in the binomial factors both have a negative sign, you can immediately choose the correct answer (A).
Or, you can use Descartes' rule of signs, which tells you that the two sign changes in the coefficients (+-+) mean there are 2 positive real roots.
