1960 AMC 12 Problem 28

Attempt Problem 28 of the 1960 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1960 AMC 12 solutions, or check the answer key.

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28.

The equation x7x3=37x3 x-\frac7{x-3}=3-\frac7{x-3} has:

infinitely many integral roots

no root

one integral root

two equal integral roots

two equal non-integral roots

Answer: B
Concepts:rational equationalgebraic manipulation
Difficulty rating: 890
Small Hint:

The identical fractional terms cancel wherever the equation is defined

Big Hint:

Check whether the resulting value lies in the original domain

Solution:

For x3,x\ne3, subtracting the identical fractions from both sides leaves x=3.x=3. But x=3x=3 makes the original denominators zero, so it is not in the domain. The equation has no root.

Therefore, the correct answer is B.

← Problem 27#27
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