Question 142722
example:
6√7 - 2 √28 

= 6*sqrt(7) - 2*sqrt(4*7)

= 6*sqrt(7) - 2*2*sqrt(7)

= 6*sqrt(7) - 4*sqrt(7)

= 2*sqrt(7)
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and 
√32 ∙ √144

= sqrt(16*2) * sqrt(144)

= 4*sqrt(2) *12

= 48*sqrt(2)
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Cheers,
Stan H.