1

Set 4: Quadratic Equations (Intermediate)

Explanation

Answer: A

For what kk does y=x2+ky = x^2 + k intersect y=2xy = 2x exactly once?

A.

1

✓ Correct
B.

-1

C.

0

D.

4

Detailed Explanation

Choice A is correct. Choice A is the correct answer. 1. Set equal: x2+k=2xx^2 + k = 2 x. 2. Standard form: x2−2x+k=0x^2 - 2 x + k = 0. 3. For one intersection, Δ=0\Delta = 0. 4. (−2)2−4(1)(k)=0(-2)^2 - 4(1)(k) = 0. 5. 4−4k=0⇒k=14- 4 k = 0 \Rightarrow k = 1. Choice B is incorrect. Choice C is incorrect. Choice D is incorrect.

Key Steps:

•

The correct answer is 1

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.
Next →

🎯 Keep Practicing!

Master all sections for your best SAT score

📚Reading & Writing→📖Vocabulary→