Sienna is solving the quadratic equation by completing the square.3x2 + 9x – 4 = 0 3x2 + 9x = 4 A(x2 + 3x) = 4

Factor 3 out of the left side of 3x² + 9x = 4. This gives 3(x² + 3x) = 4, so A = 3. The correct choice is 3.

AI-written and checked against the verified answer.