2020 AMC 10A Problem 5

Attempt Problem 5 of the 2020 AMC 10A below, then check your answer against the video solution and professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2020 AMC 10A solutions, or check the answer key.

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5.

What is the sum of all real numbers xx for which x212x+34=2?|x^2-12x+34|=2?

1212

1515

1818

2121

2525

Answer: C
Concepts:absolute valuequadratic
Difficulty rating: 1020
Video solution:
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Written solution:

The equation means x212x+34=2x^2-12x+34=2 or x212x+34=2x^2-12x+34=-2. The first gives x212x+32=0x^2-12x+32=0, with roots 44 and 88. The second gives (x6)2=0(x-6)^2=0, with root 66. The sum of all real solutions is 4+8+6=184+8+6=18. Thus, C is the correct answer.

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