Set 15: Quadratic Equations (Intermediate)

Explanation

Answer: A

The axis of symmetry for $y = 3x^2 + 12x + 5$ is:

$x = -2$

✓ Correct

$x = 2$

$x = -4$

$x = -6$

Detailed Explanation

Choice A is correct. Choice A is the correct answer. Use the formula $x = -b/2 a$ . 1. $a = 3$ , $b = 12$ . 2. $x = -12 / (2 \times 3)$ . 3. $x = -12 / 6 = -2$ . Choice B is incorrect because of a sign error. Choice C is incorrect because it divides by $a$ instead of $2a$ ( $12 /3=4$ ). Choice D is incorrect because it divides by 2 only.

Key Steps:

•

The correct answer is $x = -2$

Why others are wrong:

B: Choice B is incorrect and may result from a calculation error.

C: Choice C is incorrect and may result from a calculation error.

D: Choice D is incorrect and may result from a calculation error.

← Previous Next →

🎯 Keep Practicing!

Master all sections for your best SAT score

📚Reading & Writing→📖Vocabulary→