Question

Considerando √5=2,24,calcule o valor aproximado de -4
√20

Answer 1

-4√20 = -4 . √(4.5) = -4.2.√5 = -8 . 2,24 = -17,92

Answer 2

Sendo √5 = 2,24, temos:

= - 4.√20

= - 4.√4.√5

= - 4 . 2 . √5

= - 4 . 2 . 2,24

= - 8 . 2,24

= - 17,92

Resp.:  - 17,92
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Obs.: 

20: 2
10: 2
5: 5
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1    = 2².5 = 4.5 = √4.√5 = 2√5