exam Maths Puzzle Numerical Ability

I would appreciate help with this problem. Thank you!
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exam Other Question

Use product rule to multiply.

sqrt (72) * sqrt (2)

My solution was to multiply sqrt (72) *sqrt (2) = sqrt 144 which is simplified to 12. Not sure if it should be simplified to 144 or 12.

Thanks! EXPRESS AS A POLYNOMIAL: x + a(x^2-ax/ x)