What is the square root of 9 − 4√5?
Correct answer A. √5 − 2
Explanation
9 − 4√5 = (√5)² + 2² − 2 × 2 × √5 = (√5 − 2)². Since √5 > 2, the positive square root is √5 − 2.
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Correct answer A. √5 − 2
9 − 4√5 = (√5)² + 2² − 2 × 2 × √5 = (√5 − 2)². Since √5 > 2, the positive square root is √5 − 2.
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