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Solve using the quadratic formula 1

Solve using the quadratic formula 1-example-1

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Answer:

Explanation:

Unless we set x^2 + 8x + 15 equal to zero, we don't have an equation to be solved. I will assume that the problem is actually x^2 + 8x + 15 = 0.

The coefficients of this quadratic are {1, 8, 15}, and so the "discriminant" b^2 - 4ac is (8)^2 - 4(1)(15), or 4. Because the discriminant is positive, we know that there are two real, unequal roots.

Continuing with the quadratic formula and knowing that the discriminant is 4, we get:

-8 ± √4 -8 ± 2

x = ---------------- = --------------- , or x = -2 ± 1: x = -3 and x = -5

2 2

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