Find the smallest positive integer such that is a perfect square.
Answer and explanation
Correct answer: D. 10
- Step 1: Factorise: .
- Step 2: A perfect square needs every exponent even, so multiply by the primes with odd exponent: .
Answer
10.
Why not the others: 40: it uses itself. 20: an extra factor is included. 7: it adds the prime factors.
Practise more Properties of Integers.
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