How did they get -3 for this problem?
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Answer:
Step-by-step explanation:
Solve x^2 + 6x + 4. Here the coefficients of the quadratic are a = 1, b = 6 and c = 4. The discriminant is therefore b^2-4ac, or, in this case, 6^2-4(1)(4), or 20.
The roots are:
-6 ± √20
x = ---------------- = -3 ± √4√5: x = -3 + 2√5 and x = -3 - 2√5
2
The -3 comes from the -6/2 in the application of the quadratic formula.
Answer A is correct.