Solve (x + 3)2 + (x + 3) – 2 = 0.Let u = xx + 3(x + 3)²x²

The repeated expression in the equation is x + 3, so set u = x + 3. Then the equation becomes u² + u − 2 = 0, which is simpler to solve. Therefore the correct choice is “x + 3.”

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