What are the solutions of the equation (x + 2)2 – 2(x + 2) – 15 = 0? Use u substitution to solve.

Let u = x + 2. Then the equation becomes u² − 2u − 15 = 0, which factors as (u − 5)(u + 3) = 0, so u = 5 or u = −3. Substituting back, x + 2 = 5 gives x = 3, and x + 2 = −3 gives x = −5. The solutions are x = −5 and x = 3, choice B.

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