9

Set 10: Quadratic Equations

Explanation

Answer: A

What is the maximum value of the function f(x)=−3x2+12x−5f(x) = -3x^2 + 12x - 5?

A.

7

✓ Correct
B.

-5

C.

12

D.

2

Detailed Explanation

Choice A is correct. Choice A is the correct answer. 1. Find Vertex x: x=−b/2a=−12/(2(−3))=2x = -b/2 a = -12 / (2(-3)) = 2. 2. Find Max Value: Substitute x=2x=2 into f(x)f(x). f(2)=−3(2)2+12(2)−5f(2) = -3(2)^2 + 12(2) - 5 f(2)=−12+24−5=7f(2) = -12 + 24 - 5 = 7. Choice B is incorrect because it is the y-intercept. Choice C is incorrect. Choice D is incorrect because it is the x-coordinate.

Key Steps:

•

The correct answer is 7

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.
← PreviousNext →

🎯 Keep Practicing!

Master all sections for your best SAT score

📚Reading & Writing→📖Vocabulary→